Manual of Patent Practice

Section 3: Inventive step

Sections (3.01 - 3.101) last updated: January 2019.


This section of the Manual is presented as three sub-sections:

  • general approach & legal background
  • examining for inventive step
  • assessing obviousness

The third sub- section provides some of the more prominent methods for answering the final question in the Windsurfing/Pozzoli approach – ie “is it obvious?”


s.130(7) is also relevant

This section is concerned with the second of the tests for patentability set out in s.1(1). It is intended to have, as nearly as practicable, the same effect as the corresponding provisions of the EPC, PCT and CPC, ie Article 56 of the EPC.


The question of whether or not an invention is obvious is a matter which is normally decided on the technical facts of the particular case rather than on any general legal principles, but insofar as any such principles can be derived from decisions given under previous legislation they will generally continue to be relevant.

Section 3
An invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art by virtue only of section 2(2) above (and disregarding section 2(3) above).


What constitutes an inventive step may depend on the nature of the invention. The matter was considered by Lord Hoffmann in Biogen Inc v Medeva plc [1997] RPC 1 (at page 34) as follows:

Whenever anything inventive is done for the first time it is the result of the addition of a new idea to the existing stock of knowledge. Sometimes, it is the idea of using established techniques to do something which no one had previously thought of doing. In that case the inventive idea will be doing the new thing. Sometimes it is finding a way of doing something which people had wanted to do but could not think how. The inventive idea would be the way of achieving the goal. In yet other cases, many people may have a general idea of how they might achieve a goal but not know how to solve a particular problem which stands in their way. If someone devises a way of solving the problem, his inventive step will be that solution, but not the goal itself or the general method of achieving it.

Obviousness must be decided on an objective test


EPC aa.52& 56 is also relevant

The test for obviousness should, as far as is possible, be an objective one. The question is whether the invention would have been obvious to a skilled person in the art, and not whether it was or would have been obvious to the inventor or to some other particular worker. It is immaterial whether the invention was the result of independent work and research done without knowledge of the prior art (Allmanna Svenska Elektriska AB v The Burntisland Shipbuilding Co Ltd, 69 RPC 63 at page 70). Although evidence of what was in the inventor’s mind may be admissible as evidence of the state of the art, it would seldom be otherwise admissible (The Wellcome Foundation v VR Laboratories (Australia) Pty. Ltd, [1982] RPC 343). The EPO Board of Appeal has held that the subjective achievement of the inventor is not relevant; the fact that an invention relating to steel refining came, not from the steel industry, but from an applicant who normally deals with other fields of technology is not evidence for the existence of an inventive step (Decisions T36/82, OJEPO 7/83).


In the judgment of the Court of Appeal in Windsurfing International Inc. v Tabur Marine (Great Britain) Ltd, [1985] RPC 59 (in considering whether claims relating to a sailboard were obvious) it was stated that:

the question of whether the alleged invention was obvious has to be answered objectively by reference to whether, at the material time (that is, immediately prior to the priority date), the allegedly inventive step or concept would have been obvious to a skilled addressee” and that “what has to be determined is whether what is now claimed as inventive would have been obvious, not whether it would have appeared commercially worthwhile to exploit it


In Molnlycke AB v Procter & Gamble Ltd [1994] RPC 49 the Court of Appeal recognised the usefulness of the analysis formulated in Windsurfing but did not consider that it assisted to ask whether the patent discloses something sufficiently inventive to deserve the grant of a monopoly. The criterion for deciding the issue of inventive step as laid down by statute was held to be a wholly objective qualitative and not quantitative test.


The Court of Appeal followed Windsurfing in Hallen Co v Brabantia (UK) Ltd [1991] RPC 195, observing that “obvious” in s.3 is not directed to whether an advance is “commercially obvious” and stating:

We do not think that the hypothetical technician must also be taken as applying his mind to the commercial consequences which might follow if the step or process in question were found in practice to achieve or assist the objective which he had in view.

However the Court of Appeal has more recently appeared to retreat from this position, stating in Dyson Appliances Ltd v Hoover Ltd [2002] RPC 22 that:

commercial realities cannot necessarily be divorced from the kinds of practical outcome which might occur to the skilled addressee as worthwhile

and so it followed that a:

commercial mindset will have played a part in setting the notional skilled addressee’s mental horizon


In Petra Fischer’s Application [1997] RPC 899 it was held that a diesel cabriolet was obvious even though there may be commercial prejudice against the idea; Jacob J stated that:

The patentee in her patent has told the skilled man nothing which he did not know before, to whit, that in the engine space of a basic production model he could put a diesel engine, if he wanted to. Whether it was worth doing that or not is another matter. Whether he thinks it will sell or not, that is another matter


It is also unsound to fasten on the word “step” and to look at the steps which were actually taken by the inventor; this interpretation places too much weight on the choice of the particular word “step” whereas the word used in the French and German texts of the corresponding provisions of the European Patent Convention means “activity” (judgment of Court of Appeal in Genentech Inc’s Patent [1989] RPC 147 at page 275). It is necessary to ask by what routes it would have been possible for the skilled person to proceed to the goal (ie the invention) from the starting point, considering how obstacles might be overcome or avoided on any such route, not only that followed by the inventor.

Structured approach needed when assessing obviousness


Anyone who is considering the question of whether or not an invention is obvious must beware of hindsight or ex post facto analysis. It can be very easy to be misled by a line of reasoning that involves working forward from the stated problem in a succession of easy steps when one knows the desired solution. In particular one must avoid looking at a prior publication under the influence of the patent or patent application in question, and one should attempt to place oneself in the shoes of the skilled person faced with the problem at hand. This is necessarily an artificial position, since the patent or patent application presents both the solution (the invention) as well as the problem (or instead of the problem, a pointer to the problem since, in some cases, one may be only able to infer this from the description of the invention).

The four-step Windsurfing approach


In Windsurfing International Inc. v Tabur Marine (Great Britain) Ltd, [1985] RPC 59, the Court of Appeal held that the question of obviousness

has to be answered, not by looking with the benefit of hindsight at what is known now and what was known at the priority date and asking whether the former flows naturally and obviously from the latter, but by hypothesizing what would have been obvious at the priority date to a person skilled in the art to which the patent in suit relates.

Thus the court formulated a four-step approach to assessing obviousness:

(1) Identify the claimed inventive concept.

(2) Assume the mantle of the normally skilled but unimaginative addressee in the art at the priority date and to impute to him what was, at that date, common general knowledge of the art in question.

(3) Identify what, if any, differences exist between the matter cited as being “known or used” and the alleged invention.

(4) Decide, without any knowledge of the alleged invention, whether these differences constitute steps which would have been obvious to the skilled person or whether they require any degree of invention.

The Windsurfing/Pozzoli approach; a reformulation of the Windsurfing approach


In Pozzoli SPA v BDMO SA [2007] EWCA Civ 588, Jacob LJ restated and elaborated upon the Windsurfing approach. This decision of the Court of Appeal does not formally replace, supersede or supplant the Windsurfing approach. It is included here because it gives an insight to the Court’s latest thinking on obviousness, and for its very useful discussion of the processes that should be adopted when one uses the Windsurfing approach. There is no suggestion that outcomes will be any different under the Pozzoli reformulation, it is a matter of style and clarity of approach and not substance. It follows that Windsurfing and Pozzoli taken together should now be seen as the precedent for deciding questions of obviousness.


At paragraph 23 of Pozzoli, Jacob LJ reformulated the Windsurfing approach as follows:

(1)(a) Identify the notional “person skilled in the art”

(1)(b) Identify the relevant common general knowledge of that person;

(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;

(3) Identify what, if any, differences exist between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;

(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

The reasoning behind this reformulation is set out at paragraphs 15 & 16 of Pozzoli :

First one must actually conduct the first two operations in the opposite order – mantle first, then concept. For it is only through the eyes of the skilled man that one properly understand what such a man would understand the patentee to have meant and thereby set about identifying the concept.

Next, that first step actually involves two steps, identification of the attributes of the notional “person skilled in the art” (the statutory term) and second identification of the common general knowledge (“cgk”) of such a person.”

Later, at paragraphs 21 & 22, Jacob LJ discusses the prior art and the third step in the Windsurfing approach:

Identification of the concept is not the place where one takes into account the prior art. You are not at this point asking what was new. Of course the claim may identify that which was old (often by a pre-characterising clause) and what the patentee thinks is new (if there is characterising clause) but that does not matter at this point.

The third step also requires a little reformulation – Windsurfing was a case under the 1949 Act where the statutory words for the prior art were “known or used”. The European Patent Convention uses the words “state of the art”.”


In Lalvani et al’s Patent BLO/220/13 the hearing officer addressed the question of whether, following the decision in Human Genome Sciences v Eli Lilly [2011] UKSC 51, [2012] RPC 6 the Office should follow the problem-solution approach of the EPO when deciding questions of obviousness. The hearing officer decided that although decisions of the EPO Boards of Appeal are persuasive, the Office is bound to follow the reformulated Windsurfing approach set out by the Court of Appeal in Pozzoli.

What does this “4-step” approach do?


In DSM NV’s Patent [2001] RPC 35, Neuberger J pointed out that the four-step Windsurfing approach ends up with the original issue to be resolved being embodied in the final question. Nevertheless it was held appropriate to apply this structured approach in order to ensure a reasoned, methodical and consistent analysis of obviousness,

not merely because it has been approved and applied in a number of previous cases, including in the Court of Appeal. It is also because it ensures that one does not go straight to the question of obviousness by reference to a general impression as to the evidence as a whole. By adopting the structured approach one ensures that there is a measure of discipline, reasoning and method in one’s approach. Indeed, it helps to ensure that there is consistency of approach in different cases involving the issue of obviousness.


Thus the first three steps of the Windsurfing/Pozzoli approach are preliminary or preparatory steps to put one in the proper frame of mind to answer the question posed in the fourth step; and the final step of the Windsurfing/Pozzoli approach can be seen as a restatement of the statutory test for inventive step – ie “is it obvious?”

Consequences of not using the Windsurfing/Pozzoli approach


The Court of Appeal in Wheatley v Drillsafe Ltd [2001] RPC 7, in overturning the decision of the Patents Court on obviousness, highlighted how a failure to use the structured Windsurfing approach to assessing obviousness had led the Patents Court to fall into the trap of using hindsight and to fail to distinguish what was known from what was common general knowledge.



Special consideration is needed when an invention may be to a combination or a collocation. In SABAF SpA v MFI Furniture Centres Ltd [2005] RPC 10, Lord Hoffmann held that before you can ask whether the invention involves an inventive step, you first have to decide what the invention is. In particular, the first step is to decide whether you are dealing with one invention or, for the purposes of s.3, two or more inventions. If two integers interact upon each other, if there is synergy between them, they constitute a single invention having a combined effect and one applies s.3 to the idea of combining them. But if each integer performs its own proper function independently of any of the others, and the claim is a mere aggregation or juxtaposition of features, then each is, for the purposes of s.3, a separate invention. The combination of a series of known or obvious features, each playing its usual part in the final entity, will be a matter of design or mere collocation, not of invention, and objection should be raised under s.3 (for discussion of anticipatory disclosures in multiple documents see also 2.09)

In this decision, Lord Hoffmann quoted with approval passages from the EPO Guidelines for Substantive Examination, providing guidance on how to determine whether two features display synergy. This guidance was re-stated and further explained in the EPO Technical Board of Appeal decision in T 1054/05:

Two features interact synergistically if their functions are interrelated and lead to an additional effect that goes beyond the sum of the effects of each feature taken in isolation. It is not enough that the features solve the same technical problem or that their effects are of the same kind and add up to an increased but otherwise unchanged effect.

The individual steps of the Windsurfing/Pozzoli approach


What follows are some discussions of some of the steps within the Windsurfing/Pozzoli approach, and some of the factors that will influence one’s thinking when using the Windsurfing/Pozzoli approach.


One may also wish to consider the discussions of these steps available in guides such as “Terrell on the Law of Patents” 16th (2006) Edition and the “CIPA Guide to the Patents Acts” (8th Edition). The locations of the relevant discussions in these guides are summarized in the table below.

Topic Terrell CIPA Guide
person skilled in the art 8.01, 12.73 3.07
common general knowledge 8.56, 12.54 3.11
identifying the inventive concept 12.74 3.18
identification of differences 12.80 3.25
difference involves an inventive step 12.81 3.26

The skilled person


The “person skilled in the art” is not a highly skilled expert or a Nobel prize winner, nor is he some form of lowest common denominator. Instead he is best seen as someone who is good at their job, a fully-competent worker. To a large degree the capacities of the skilled person will be determined by the nature of the common general knowledge identified as being “relevant”. An important consequence of imparting to this person the relevant common general knowledge is that he will generally not be aware of individual patent specifications, scientific papers, or the like – see the extract from General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd at 3.32 below.


He should be taken to be a person who has the skill to make routine workshop developments but not to exercise inventive ingenuity or think laterally - as set out, for example, by Laddie J in Pfizer Ltd’s Patent [2001] FSR 16 at paragraphs 62 and 63, and by the Court of Appeal in Technip France SA’s Patent [2004] RPC 46, per Jacob LJ at paragraphs 6 to 10, who held that the person skilled in the art, if real, would be very boring - a nerd.


His level of skill will, however, depend on the scope of the subject matter of the patent in question (see, for example, Dyson Appliances Ltd v Hoover Ltd [2001] RPC 26, upheld by the Court of Appeal [2002] RPC 22; see also 14.75)


He is assumed to be at least sufficiently interested to address his mind to the subject and to consider the practical application of the information which he is deemed to have (see Windsurfing International Inc. v Tabur Marine (Great Britain) Ltd [1985] RPC 59). While recognising this, the Court of Appeal in PLG Research Ltd and anr. v Ardon International Ltd and others [1995] RPC 287 held that knowing a piece of prior art is one thing but appreciating its significance to the solution to the problem in hand was another. Whitford J had similarly warned in Sandoz Ltd (Frei’s Application) [1976] RPC 449 against too ready an assumption that the significance of existing published material in relation to the problem dealt with would necessarily be apparent to the hypothetical skilled person.


The skilled person should not be expected to try all combinations unless he has a problem in mind and particular combinations might assist him in solving it; he is not to be expected to take steps or try processes which he would not regard as worthwhile as a possible means of achieving or assisting in practice the objective which he has in view (see the judgment of the Court of Appeal in Hallen Co v Brabantia (UK) Ltd [1991] RPC 195, see also 3.07.


Although obviousness generally is assessed on the basis of technical rather than commercial considerations the Court of Appeal in Dyson v Hoover see 3.07 appeared to indicate a softening of that approach, holding that commercial realities cannot always be divorced from the kinds of practical outcome which might appear worthwhile to the skilled addressee and that commercial considerations will play a part in the mindset of the skilled person.

The skilled person seeks expert advice, and can be considered a team


With a prospective solution in mind, the skilled person might need to seek advice from an expert in another field. In Tetra Molectric Ltd v Japan Imports Ltd ([1976] RPC 547) the Court of Appeal held that a claim to a smoker’s lighter using piezoelectric ignition was obvious. Since the possibility of using piezoelectricity in a lighter would have occurred to the industry, a skilled lighter manufacturer, himself not an expert in piezoelectricity, could reasonably be expected to seek advice from those who were. If such experts had been consulted, they would have advised that the suggestion was definitely worth trying, and they could have solved such problems as arose. The person skilled in the art may, in such circumstances, be regarded as combining his own common general knowledge with expert advice from the other field.


Alternatively the hypothetical skilled person acting under expert advice can be seen as a team composed of skilled persons from each of the relevant fields, see Genentech Inc’s Patent [1989] RPC 147 at pages 278 & 280 or Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2006] RPC 2 at paras 39 & 40. Where the skilled person is represented by a team of individuals each practicing their particular art, it makes no difference whether they work together as a single unit or as sub-contractors. The standard for skills is the same. In the example of the piezoelectric lighter above the team might be composed of a skilled person from the field of piezoelectricity and a skilled person from the field of lighter manufacture. (See also 3.44 & 3.83).


However, it cannot be assumed – for the purpose of assessing inventive step – that the “person skilled in the art” necessarily comprises a team made up of experts with all the different skills needed to perform the invention. In Schlumberger Holdings Ltd v Electromagnetic Geoservices AS [2010] RPC 33, the Court of Appeal considered the inventiveness of a method for oil exploration which utilised an electromagnetic surveying technique known as CSEM to determine whether a potential undersea reservoir actually contained oil or gas. CSEM was a known technique, but this application of it had not been contemplated. Jacob LJ held that the correct approach was to ask whether the exploration geophysicist would realise that there was a solvable problem and that CSEM might realistically be the solution. The problem also needed to be approached from the other side; would the CSEM expert be aware of the exploration geophysicist’s problem and appreciate that CSEM was a potential solution?

if it would not be obvious to either of the notional persons or teams alone and not obvious to either sort of team to bring in the other, then the invention cannot fairly be said to be obvious.


Jacob LJ held that in such a case, the “person skilled in the art” for the assessment of inventiveness under s.3 (Art. 56 EPC) was not necessarily the same person or team as that used to assess sufficiency (see 14.75) or the scope of the claims. For the latter two purposes, this “person” would be a person or team with all the skills necessary to perform the invention – in this case, an exploration geophysicist and a CSEM expert. This was not necessarily the case for inventiveness, if there was no reason for this team to be assembled without the benefit of hindsight.


The question of whether a team with disparate skills would be assembled was also at issue in Mutoh Industry Ltd’s Application ([1984] RPC 35). In this case, the hearing officer held that a drawing board employing magnetic bearings was obvious, since it was reasonable for the drawing-board man concerned with the problem of reducing friction to consult a bearings expert. The Patents Court however allowed an appeal, finding that users of the known device were not struggling to overcome a problem which inhibited their activities, nor were manufacturers failing to put the known device on the market because it was not sufficiently friction-free; there was therefore no reason for the manufacturer or user to look for outside assistance. In ABT Hardware Ltd’s Application BL O/36/87, the hearing officer distinguished the circumstances from those in Mutoh and held the invention to be obvious. It was concerned with the use in a letterplate of a known type of magnet comprising an elastomer loaded with ferrite powder to hold a flap in sealing engagement with a frame over an opening in the frame. There were specific problems associated with prior magnetic letterplates which could arguably have led the applicants to seek specialist advice, and the general availability and widespread use of the magnets in question might also reasonably be expected to have led the applicants naturally to consider their adoption in letterplates, with or without consultation of specialists.

Common general knowledge


One cannot overstate the importance of the notion of common general knowledge. It is central to everything that is required of the hypothetical skilled person, for example in reading and understanding the patent for the purposes of purposive construction, or in understanding and reacting to the cited prior art. Common general knowledge can, perhaps, be summarized as a part of the mental equipment or mental toolkit needed so as to be competent in the art concerned. It is what makes the skilled person skilled.


The courts have attempted to define the common general knowledge many times over the years. In Raychem Corp’s Patents [1998] RPC 31 Laddie J explained common general knowledge as follows:

The common general knowledge is the technical background of the notional man in the art against which the prior art must be considered. This is not limited to material he has memorized and has at the front of his mind. It includes all that material in the field he is working in which he knows exists, which he would refer to as a matter of course if he cannot remember it and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art. This does not mean that everything on the shelf which is capable of being referred to without difficulty is common general knowledge nor does it mean that every word in a common text book is either. In the case of standard textbooks, it is likely that all or most of the main text will be common general knowledge. In many cases common general knowledge will include or be reflected in readily available trade literature which a man in the art would be expected to have at his elbow and regard as basic reliable information.


In Teva UK Limited & Anor v AstraZeneca AB [2014] EWHC 2873 (Pat) Sales J said that guidance on what constitutes common general knowledge (CGK) needs to be kept up to date in the age of the internet and digital databases of journal articles. He stated that searches of databases are part and parcel of the routine sharing of information in the scientific community and are an ordinary research technique, and further added that:

if there is sufficient basis … in the background CGK relating to a particular issue to make it obvious to the … skilled person that there is likely to be – not merely a speculative possibility that there may be – relevant published material bearing directly on that issue which would be identified by such a search, the relevant CGK will include material that would readily be identified by such a search.


A set of industry standards may be considered to be part of the common general knowledge, even if they are of such length and complexity that no skilled worker could possibly be expected to know even a fraction of the information contained therein, providing the skilled person would know where to find the information relevant to the task in hand (Nokia v Ipcom [2010] EWHC 3482; upheld at appeal [2011] EWCA Civ 6).


Unconventional knowledge can still be part of the common general knowledge. In Apimed Medical Honey Ltd v Brightwake Ltd [2011] EWPCC 2, [2011] RPC 16, the patent concerned surgical dressings for wounds comprising honey and a gelling agent. The court held that, at the priority date, there may have only been a few people working within the wound care field who would have seen a clinical future in treating wounds with honey, but that fact did not eliminate the idea from being a part of the common general knowledge.


In Generics (UK) Ltd (t/a Mylan) v Warner-Lambert Company LLC [2015] EWHC 2548 Arnold J held that matter being relied on as common general knowledge must be common general knowledge in the UK. He explained:

“The reason for this is that, whether one is concerned with the validity of a European Patent (UK), or a UK patent, one is concerned with a right in respect of the UK. It is true that the prior art may have been published anywhere in the world, but I do not think that alters the need for the skilled team to consider that art as if they were located in the UK. I do not think it matters that a fact was common general knowledge in (say) China, if it was not common general knowledge here. The position may be different if all the persons skilled in a particular art in the UK are acquainted with the position in China”.


A much older definition comes from Fletcher-Moulton LJ in British Ore Concentrate Syndicate Ltd v Minerals Separation Ltd (1909) 26 RPC 124 (the reference to “public general knowledge” should be read as common general knowledge):

[The court] has to arrive as closely as it can at the mental attitude of a well- instructed representative of the class to whom the Specification is addressed, and no more. In other words, in the performance of this part of its task it has to ask itself what ought fairly to be considered to be the state of knowledge in the trade or profession at the date of the patent with respect to the matters in question, and if any facts or documents are such that in ordinary probability they would not be known to competent members of such trade or profession they ought not to be taken, either for or against the public on the one hand, or the inventor on the other, as forming part of public general knowledge.


A much longer passage from the speech by Sachs LJ in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 is of particular interest because it sets out the relationship of patent specifications to the common general knowledge (“it is clear that individual patent specifications and their contents do not normally form part of the relevant common general knowledge”). It also sets out the relationship of scientific journals and papers to the common general knowledge (“it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal”). This passage is taken from pages 482-483 of the General Tire judgment:

The common general knowledge imputed to such an addressee must, of course, be carefully distinguished from what in patent law is regarded as public knowledge. This distinction is well explained in Halsbury’s Laws of England, Vol. 29, para. 63. As regards patent specifications it is the somewhat artificial (see per Lord Reid in the Technograph case [1971] FSR 188 at 193) concept of patent law that each and every specification, of the last 50 years, however unlikely to be looked at and in whatever language written, is part of the relevant public knowledge if it is resting anywhere in the shelves of the Patent Office. On the other hand, common general knowledge is a different concept derived from a commonsense approach to the practical question of what would in fact be known to an appropriately skilled addressee—the sort of man, good at his job, that could be found in real life.

The two classes of documents which call for consideration in relation to common general knowledge in the instant case were individual patent specifications and ‘widely read publications’.

As to the former, it is clear that individual patent specifications and their contents do not normally form part of the relevant common general knowledge, though there may be specifications which are so well known amongst those versed in the art that upon evidence of that state of affairs they form part of such knowledge, and also there may occasionally be particular industries (such as that of colour photography) in which the evidence may show that all specifications form part of the relevant knowledge.

As regards scientific papers generally, it was said by Luxmoore J. in British Acoustic Films (53 RPC 221 at 250):

In my judgment it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal may be, in the absence of any evidence that the disclosure is accepted generally by those who are engaged in the art to which the disclosure relates. A piece of particular knowledge as disclosed in a scientific paper does not become common general knowledge merely because it is widely read, and still less because it is widely circulated. Such a piece of knowledge only becomes general knowledge when it is generally known and accepted without question by the bulk of those who are engaged in the particular art; in other words, when it becomes part of their common stock of knowledge relating to the art.’

And a little later, distinguishing between what has been written and what has been used, he said:

It is certainly difficult to appreciate how the use of something which has in fact never been used in a particular art can ever be held to be common general knowledge in the art.’

Those passages have often been quoted, and there has not been cited to us any case in which they have been criticised. We accept them as correctly stating in general the law on this point, though reserving for further consideration whether the words ‘accepted without question’ may not be putting the position rather high: for the purposes of this case we are disposed, without wishing to put forward any full definition, to substitute the words ‘generally regarded as a good basis for further action’.”


Over time the growth of proprietary and specialist knowledge, that is knowledge known only within certain organisations or companies or known only to a few experts, makes it increasingly difficult to distinguish the common general knowledge from the state of the art. Although a feature, item or concept may be well-known to a few, it is not part of the common general knowledge unless it can be shown to be known to and accepted by the large majority of those skilled in the art. In Beloit v Valmet (No.2) [1997] RPC 489 Aldous L.J. put it as follows:

It has never been easy to differentiate between common general knowledge and that which is known by some. It has become particularly difficult with the modern ability to circulate and retrieve information. Employees of some companies, with the use of libraries and patent departments, will become aware of information soon after it is published in a whole variety of documents; whereas others, without such advantages, may never do so until that information is accepted generally and put into practice. The notional skilled addressee is the ordinary man who may not have the advantages that some employees of large companies may have. The information in a patent specification is addressed to such a man and must contain sufficient details for him to understand and apply the invention. It will only lack an inventive step if it is obvious to such a man. It follows that evidence that a fact is known or even well-known to a witness does not establish that that fact forms part of the common general knowledge. Neither does it follow that it will form part of the common general knowledge if it is recorded in a document.


The Hearing Officer in Maxluck Biotechnology’s Application BL O/130/10 highlighted (citing Ratiopharm GmbH v Napp Pharmaceutical Holdings [2009] RPC 11) the dangers of selectivity in deciding what is common general knowledge in the field:

However, when deciding what is common general knowledge, one cannot just take those parts of it that support (or rebut) the objection that is being made. To do so opens oneself up to an accusation of ex post facto selection. The notional skilled person comes armed with all the common general knowledge and cannot pick and choose selectively with the benefit of hindsight. Some aspects of the common general knowledge may lead the skilled person from the prior art towards the inventive concept; but equally other aspects of common general knowledge may lead him away from the inventive concept.


The Patents Court in KCI Licensing Inc & Ors v Smith & Nephew Plc & Ors [2010] EWHC 1487 identified a further class of information, which, although not part of the common general knowledge, may nevertheless be taken into account in determining obviousness. In a passage endorsed by the Court of Appeal ([2010] EWCA Civ 1260), Arnold J observed that:

even if information is neither disclosed by a specific item of prior art nor common general knowledge, it may nevertheless be taken into account as part of a case of obviousness if it is proved that the skilled person faced with the problem to which the patent is addressed would acquire that information as a matter of routine. For example, if the problem is how to formulate a particular pharmaceutical substance for administration to patients, then it may be shown that the skilled formulator would as a matter of routine start by ascertaining certain physical and chemical properties of that substance (e.g. its aqueous solubility) from the literature or by routine testing. If so, it is legitimate to take that information into account when assessing the obviousness of a particular formulation. But that is because it is obvious for the skilled person to obtain the information, not because it is common general knowledge.

Identifying the inventive concept


Applying Windsurfing International v Tabur Marine and Molnlycke v Procter & Gamble Jacob J observed in Unilever PLC v Chefaro Proprietaries Ltd [1994] RPC 567 at page 580 that it is the inventive concept of the claim in question which must be considered, not some generalised concept to be derived from the specification as a whole. Different claims can, and generally will, have different inventive concepts. The first stage in identifying the inventive concept of a claim is likely to involve a purposive construction of the claim (see 125.14) – what does it mean to the skilled person? However merely doing that can be too wooden because one does not distinguish between portions which matter and portions which, although limiting the ambit of the claim, do not. It is the essence of the claim that should be identified when considering the inventive concept. Finding that essence will involve constructing something akin to a précis, stripping out unnecessary verbiage from the purposively construed claim.


In Generics (UK) Limited and others v H Lundbeck A/S [2009] UKHL 12, [2009] RPC 13, Lord Walker explained that there is a difference between the “inventive concept” of a claimed invention and its “technical contribution to the art”. He stated at paragraph 30:

Inventive concept” is concerned with the identification of the core (or kernel, or essence) of the invention—the idea or principle, of more or less general application (see Kirin-Amgen [2005] RPC 169 paras 112-113) which entitles the inventor’s achievement to be called inventive. The invention’s technical contribution to the art is concerned with the evaluation of its inventive concept—how far forward has it carried the state of the art? The inventive concept and the technical contribution may command equal respect but that will not always be the case.

This case related to a straightforward product claim. The House of Lords held that the novel and non-obvious product claimed formed the technical contribution to the art, whilst the process of how it had been made formed the inventive concept (see also Examination Guidelines for Patent Applications Relating to Chemical Inventions.


Although the inventive concept can in certain respects be broader than the claim (because immaterial features of the claim may be ignored), it cannot be narrower than the claim. In Datacard Corp. v Eagle Technologies Ltd. [2011] EWHC 244 (Pat), [2011] RPC 17, Arnold J held that the inventive concept cannot be defined in terms which apply only to a narrow sub-group of embodiments with certain technical advantages, and which do not apply to the rest of the claim. If the patentee has chosen to claim the invention broadly, the inventive concept must be of at least equivalent breadth.


In Raychem Corp.’s Patents [1998] RPC 31 (upheld on appeal - [1999] RPC 497) the practice of drafting claims in an unnecessarily complicated way was criticised. It was pointed out that a properly drafted claim will state the inventive concept concisely, but it was held that where the claims were prolix and opaque the court should break free of the language and concern itself with what they really meant.

The state of the art


The state of the art for the purposes of deciding whether an invention is obvious is defined by s.2(2); that is, it includes everything which has been made available to the public, anywhere in the world, before the priority date of the invention (see further 2.21-2.29). Matter which forms part of the state of the art by virtue of s.2(3) is specifically excluded from consideration.

3.37 [moved to 3.75.1]

Consideration of the prior art: age of documents and other criteria


Any disclosure falling within the s.2(2) field may be used as the starting-point for an inventive step objection. The objection cannot be overcome by an argument that the skilled person would simply not have discovered a document in the course of his work, if that document has been made public anywhere in the world, in any language, at any time before the priority date. (However, as discussed at 3.40-3.42, this does not necessarily apply when considering whether the skilled person would have considered a further document together with the first document, as then the likelihood of the skilled person considering the two documents together must be assessed.) For example, in Wake Forest University Health Sciences & Ors v Smith & Nephew Plc & Anor [2009] EWCA Civ 848, the prior art in question was a Russian language research paper (“Bagautdinov”) which had been shown to have been made available in four libraries in the former Soviet Union. Jacob LJ noted that it was highly unlikely that the inventor or anyone involved in the litigation knew of its existence at the priority date of the claimed invention. However, he observed (emphasis added) that “Mr Alexander [the patentee’s representative] accepts, as he must, that the skilled person will have read Bagautdinov and have done so carefully but with no imagination”. This general principle was set out by Laddie J in Pfizer Ltd’s Patent [2001] FSR 16:

A real worker in the field may never look at a piece of prior art for example he may never look at the contents of a particular public library or he may be put off because it is in a language he does not know. But the notional addressee is taken to have done so. This is a reflection of part of the policy underlying the law of obviousness. Anything which is obvious over what is available to the public cannot subsequently be the subject of valid patent protection even if, in practice, few would have bothered looking through the prior art or would have found the particular items relied on.


However, this does not mean that all prior art will be accorded equal weight or significance; any piece of prior art must be viewed through the eyes of the skilled person at the priority date, and the common general knowledge in the field may cause him to disregard it. For example, in Actavis v Merck [2008] RPC 26, the Court of Appeal considered whether the use of a drug to treat alopecia was obvious over a prior art document which disclosed the use of the same drug, to treat the same condition, at a different dosage. It was held that, at the time the document was published, the claimed invention would have been obvious from this disclosure. However, by the priority date, the accepted wisdom in the field would suggest that this drug would be ineffective at any dosage. Jacob LJ therefore highlighted the importance of assessing inventiveness at the priority date, and not before or after:

one might assume that when an invention becomes obvious it must remain so thereafter. But such an assumption would be wrong: obviousness must be determined as of a particular date. There is at least one other well-known example showing how an invention which might be held obvious on one date, would not be so held at a later date. That is where there has been commercial success following a long-felt want. Time can indeed change one’s perspective. The perspective the court must bring to bear is that of the skilled man at the priority date and not any earlier time.


An old specification which teaches specifically the solution of the problem which an invention seeks to overcome so that the skilled person should readily appreciate its significance can form a good basis for an obviousness objection (Jamesigns (Leeds) Limited’s Application [1983] RPC 68). A further example of a circumstance in which a lack of inventive step objection based on an old document could be sustained is a case where the modification of the older invention could not have been effected before recent technological advances had been made, such as the development of a new material. Documents which have resulted in practical application or which are acknowledged as well known are also likely to have greater force.


Be wary of uncritical ageism in relation to the prior art. In Brugger and others v Medic-Aid Ltd ([1996] RPC 635) Laddie J held (at 653 and 655) that:

The fact that a document is old does not, per se, mean that it cannot be a basis for an obviousness attack. On the contrary, if a development of established and ageing art is or would be obvious to the skilled worker employed by a hungry new employer, it cannot be the subject of valid patent protection even if those who have been in the trade for some time, through complacency or for other reasons, have not taken that step. Each pleaded piece of prior art must therefore be assessed as if it was being considered afresh at the priority date. It is not to be excluded from this exercise merely because it is old. There is no rule of commerce that every new product or process must be developed and put on the market or published in literature as soon as it becomes obvious.


It is only when the answer to the question “why was this not developed earlier” is “a likely and reasonable explanation is that people looking for a way round an existing problem did not see this as the answer” that the age of the prior art should play a part in meeting an obviousness attack. If it is likely that in the real world no one was looking for an answer the fact that none was found says nothing about whether the answer proposed in the patent under attack was obvious.


In Merck Sharp & Dohme Corp v Teva UK Ltd [2011] EWCA Civ 382 the argument was made that a document published only six days before the priority date was not relevant for inventiveness, as it would not have been possible to perform the steps leading from the prior art to the claimed invention in the period between the publication of the prior art and the priority date. This argument was decisively rejected by the Court of Appeal; all that needs to be decided is whether the claimed invention is obvious over the prior art, not whether there would in fact be time to arrive at the invention by the priority date.

See also 3.78-3.79, 3.80-3.81.2 and 3.97-3.101.

Combining documents, “mosaicing”


While it is not possible to combine the disclosure of a given document with other matter to demonstrate lack of novelty (see 2.09), it is permitted to combine any of the prior art (whether published documents, instances of prior use or common knowledge) in order to argue that an inventive step is lacking. However, although a single disclosure, however remote, of the whole invention will destroy novelty, in order to establish that a combination of teachings from the prior art shows an invention to be obvious, it must be likely that the skilled person would have considered those teachings together. Laddie J in Pfizer Ltd’s Patent [2001] FSR 16 at paragraph 66 stated:

When any piece of prior art is considered for the purposes of an obviousness attack, the question asked is “what would the skilled addressee think and do on the basis of the disclosure?” He will consider the disclosure in the light of the common general knowledge and it may be that in some cases he will also think it obvious to supplement the disclosure by consulting other readily accessible publicly available information. This will be particularly likely where the pleaded prior art encourages him to do so because it expressly cross-refers to other material. However, I do not think it is limited to cases where there is an express cross-reference. For example if a piece of prior art directs the skilled worker to use a member of a class of ingredients for a particular purpose and it would be obvious to him where and how to find details of members of that class, then he will do so and that act of pulling in other information is itself an obvious consequence of the disclosure in the prior art.


There is no simple rule as to whether information from different documents, or from different parts of a single document, can properly be combined as a “mosaic” to provide a case that an invention is obvious. The greater the number of documents which must be so combined to reach the invention, the more likely on the whole that there is an inventive step, but regard must be paid to the nature of the features which are combined. The combination of a series of known features, each playing its usual part in the final entity, is often simply a matter of design or mere collocation, and not of invention see 3.17.


In Dow Chemical Company (Mildner’s Patent), [1973] RPC 804, Whitford J indicated that in order to establish obviousness from a combination of documents it is necessary to consider the extent to which you can conclude that the documents are ones which the seeker after information would come across and would consider together. Two extremes that are sometimes put forward are (a) that no two documents may be combined to make a mosaic unless at least one is well known, and (b) that all the information in any set of documents can be combined provided they are all in the same art. Neither of these extremes is acceptable as a general principle. Although the second extreme may be the more likely to reflect the true situation it should not be used as a pretext for not investigating beyond the immediate field of the invention see 3.26-3.27.

Factors to consider before combining documents


In deciding whether or not it is obvious to combine the disclosure in two or more documents, the following considerations are likely to be relevant:-

(a) How the nature and the contents of the documents influence whether the person skilled in the art would combine them. For example where the disclosed features seem at first sight to have an inherent incompatibility or where one document has a tendency to lead from the mosaic, this would be a pointer towards the combinations being inventive see 3.91

(b) Whether the documents came from the same technical field or from neighbouring or remote technical fields see 3.26-3.28.2 and see 3.44

(c) The presence of references in one document to another

(d) The amount of selection required to isolate the separate disclosures from the surrounding documentary material

(e) Whether the contents of one document are so well known that the skilled person would always have them in mind in reading other documents see 3.45

(f) The age of the documents see 3.37.2-3.39.1


Where the documents are from different technical fields the question is whether the problem would have prompted search in those fields. In Dow Chemical Company (Mildner’s) Patent [1973] RPC 804, an invention residing in an electrical cable in which a plastics jacket was securely bonded to a metal shield using a specified copolymer was held to be obvious in the light of one document disclosing all the features of the cable but not mentioning the adhesive copolymer, and other documents disclosing the copolymer. Although these latter documents did not refer to cable manufacture, they did refer to the copolymer as having high moisture resistance and being suitable for bonding plastics to metal, both essential properties in adhesives for use in cables. It was therefore reasonable to expect the skilled person concerned with the problem of adhering plastics to metal in cables to have found and considered these documents. The Technical Board of Appeal of the EPO has considered it reasonable to expect a person skilled in the art, unable to fulfil a need in the relevant field, to look for suitable parallels in a neighbouring field so closely related that he would take developments therein into account, or in the broader general field in which the same or similar problems extensively arise and of which he must be expected to be aware (Decision T 176/84, OJEPO 2/86).

Combining documents with common general knowledge


If the invention can be produced by combining the teaching of one document with common general knowledge or with standard practice in the art, then even if the inventor has not conceived it nor the applicant presented it in such terms, there is a strong presumption that such a combination would be obvious to the skilled person. If, in his application, the applicant refers to prior art as “conventional”, this may be taken to indicate that the prior art is common general knowledge (NEC Corporation’s Application BL O/038/00)

Examining for inventive step

A warning against overelaborating the question of obviousness


When considering an inventive step objection the examiner should always bear in mind this warning from Jacob LJ in Angiotech Pharmaceuticals v Conor Medsystems Inc [2007] EWCA Civ 5:

one can overelaborate a discussion of the concept of “obviousness” so that it becomes metaphysical or endowed with unwritten and unwarranted doctrines, sub- doctrines or even sub-sub-doctrines. …. In the end the question is simply “was the invention obvious?

A reminder to consider obviousness whenever a novelty objection is overcome


The examiner should always consider the obviousness of a claim when a novelty objection in respect of that claim has been overcome.

Determining obviousness


The determination as to whether an invention is obvious or not is of considerable importance both to applicants and the public, and the substantive examiner must be prepared to put considerable effort into this task. It is particularly important that the examiner correctly identifies the relevant common general knowledge that is to be imparted to the skilled person. In conferring on the substantive examiner power to consider inventive step, s.18(2) implies that the examiner is required to exercise an expertise, and that he must be recognised as qualified to do so. This view has been reinforced by Pumfrey J in Degussa-Huls AG v The Comptroller-General of Patents [2005] RPC 29:

Examiners are appointed because of their general technical skills. They will, in the classes which they examine, acquire extensive knowledge and they will be able to form a clear view of the qualities which are to be expected of the person skilled in the art in that particular field.


The nature of the expertise implied depends on the matter to be determined and on the circumstances of the application. For example the substantive examiner is not in most cases in a position to deny simply from his own knowledge facts (such as whether a given technique is well-known, or whether a given reaction has specified by-products) to which evidence has been brought forward from a witness -possibly the applicant himself - who can claim relevant expert knowledge. In such circumstances the examiner is likely to have to accept the evidence from the applicant unless he can produce documentary evidence of contrary effect. Nevertheless, the substantive examiner must be taken to be qualified to decide, given the prior art and other relevant technical facts, whether the resulting position implies the presence or absence of an inventive step.

The Windsurfing/Pozzoli approach


From the discussions at the beginning of this Section it is clear that the examiner must use the Windsurfing/Pozzoli approach when deciding whether or not to object and, if objecting, setting out that objection. Before raising a lack of inventive step objection a substantive examiner should be clear in his own mind as to what point in the prior art he is starting from and the nature and number of steps it would take for a person skilled in the art to get from the starting point to the invention.


The examiner need not spend an undue amount of time in debating the precise nature of the skilled person, whether that person is a designer, a technician, a manufacturer, etc. As indicated in 3.20 the character of this person is largely set by the relevant common general knowledge imparted to them, rather than their position in any organizational chart.


In Eli Lilly & Co. v Human Genome Sciences, Inc. [2008] EWHC 1903 (Pat), [2008] RPC 29, which related to a patent for a polynucleotide sequence encoding a Neutrokine- polypeptide, Kitchin J. applied the Windsurfing/Pozzoli test and reached the conclusion that the claimed invention was not obvious from the prior art. However, he nevertheless held that the claims lacked an inventive step on the grounds that the patent made no technical contribution to the art and did not solve a technical problem. Kitchin J. held that this should be determined by considering whether the invention lies in making the products of the claim or rather whether the invention must lie in a disclosure that the DNA products of the claim code for useful proteins and, if so, whether the specification does no more than speculate as to what those uses might be. Any deficiency in this regard cannot be remedied by evidence coming into existence after the application has been filed. However, this objection appears to be specific to certain types of biotechnology patents, wherein the inventiveness of a nucleic acid or protein lies in the identification of its function rather than in its production per se.

Consider different starting points


A matter which requires invention when tackled from one starting point may be commonplace when started from a different disclosure or with a different known problem in mind. The applicant may for example have presented his invention as a combination of features A, B, C, D which he admits are known in combination, with a further feature E which it would undoubtedly be inventive to add to the acknowledged combination. It may be however that a prior document discloses the combination of features A and E, and that the addition of the remaining features B, C, D is then obvious.


The starting point of the invention from the point of view of the applicant may be apparent from the specification. For example, the description may contain an account of the prior art and/or the problem to be solved, or the main claim may be in the two-part form, in which a preamble specifying a set of features known in combination in the prior art is followed by a characterising portion setting out the new features. The applicant is however not obliged to do this, nor does a reader of the specification have to accept the applicant’s assessment of the invention.

No rules of thumb; precedents to be treated with caution


The decision to raise an objection of lack of inventive step must be made on a proper consideration of the facts of the particular case and any kind of rule of thumb approach should be avoided. Caution should be exercised in relying on precedent cases, since, more than with any other topic to be decided by the substantive examiner, attempts to line up a particular case with some decided case can mislead.

Raise any sound objection


The substantive examiner should not raise an objection when he has no good reason to suppose that there is no invention just to fish for a weakness in the applicant’s position. As in any other area of examination it is thoroughly bad practice for an examiner to raise an objection which, with thought, he would see was not justified, merely to pass the burden of thinking about the matter to the applicant.


However, even if he thinks he can foresee how the applicant will amend or argue to overcome the objection, the examiner should raise any sound obviousness objection. The applicant may amend in any way he thinks fit; there is no guarantee that the applicant will act as the examiner has predicted.


A substantive examiner faced with a prima facie case of obviousness which might be capable of rebuttal by special information of a sort which is not available to the examiner, but which must be available to the applicant, should always put the objection to the applicant. An example of such information is whether the applicant’s process avoids a drawback which experts in the art would expect it to have, or whether the applicant is merely prepared to tolerate the drawbacks, so that he has not made any inventive contribution. If the applicant fails to make a satisfactory answer to such an objection the examiner can safely assume that this is because the facts are against the applicant see 3.64.



In practice the guidance above on combining or “mosaicing” documents can be difficult to satisfy see 3.40–3.44. In particular the examiner must explain why he believes that the skilled person would make that combination of documents.


The examiner must always keep sight of what use he is making of the cited documents. Oftentimes the examiner is not making a true combination in the sense of using a combination of two or more documents to arrive at a solution to a particular problem. Instead the examiner will find that he is using some of those documents to illustrate the common general knowledge, acknowledged prior art or some other point as in 3.62. In these circumstances the examiner may find the combination easier to justify.

Content of the report


In addition to citing documents the first examination report should state a prima facie case, not going into overmuch detail. This prima facie case does not have to explicitly mention Windsurfing or Pozzoli, but it should leave the applicant in no doubt that the Windsurfing/Pozzoli approach has been adopted. The aim should be to oblige the applicant to state what he considers the inventive step to be and to justify his assertion. This first report should, so far as is practicable, set out explicitly any assumptions of a technical character which have been made. Where it seems unlikely that the applicant will challenge these assumptions, support for the assumptions need not be sought unless and until the applicant challenges them (but see 3.62).


Subsequent reports responding to the applicant’s amendments and/or arguments should be more detailed, explicitly setting out the examiner’s reasoning for each of the Windsurfing steps.


When matter considered to be well-known in the art is used in formulating an obviousness objection, it need not be supported by document references unless and until it is challenged. However it is probably best that all document references that the examiner will be using are put before the applicant at the earliest opportunity. When documents are cited as examples illustrating common general knowledge or background art, for example, where the contention is that the invention claimed comprises an obvious modification to known apparatus and documents are cited, one showing the modification per se and one or more others exemplifying the apparatus, this should be made clear at the outset. Documents should be included in the initial citations where necessary to substantiate background art considered to fall short of well-known. It should be made clear whether documents cited are being relied on individually or in combination and/or in conjunction with common knowledge.

Reporting both novelty and inventive step objections


In putting to the applicant objections of lack of novelty and inventive step the substantive examiner should make clear which claims are attacked on each of these grounds. Where the examiner attacks the main claims but defers consideration of the inventiveness of subordinate claims he should make this clear to the applicant (see 18.43) In attacking subordinate claims, where it is not clear what response the applicant is likely to make to the objections to the main claims, it is sufficient to indicate the general nature of an objection to lack of inventive step leaving any elaboration until this is made necessary by the applicant’s response.

Responding to the applicant’s case


An objection should not be withdrawn merely because an argued response has been submitted - the argument must be adequate to overcome the objection. In Degussa- Huls AG v The Comptroller-General of Patents [2005] RPC 29, in dismissing an appeal against the Hearing Officer’s finding of obviousness, Pumfrey J held that:

when a case of prima facie obviousness or anticipation is made out … the evidential burden shifts on to the applicant to produce evidence upon which the Examiner can properly act in saying either that there is insufficient material before him to say that the objection of obviousness is in fact made out or possibly even to say that the objection of obviousness must, on the material available to him, fail …

Where an Examiner forms a view upon what, at first sight, are sound grounds for supposing there is a strong case of obviousness, then it is up to the applicant to put convincing material in front of the Examiner upon which, as I have said, he can act contrary to what was to him the apparent position.


In that case, evidence that the invention had unforeseeable advantages which were unrelated to the reasons for the initial finding of obviousness did not overcome this finding. Evidence from the applicant, or from a witness provided by the applicant, to the effect that the situation does imply an inventive step (as distinct from evidence on a point of fact), must therefore be regarded solely as argument which the examiner accepts or rejects of his own judgment, supplemented of course by whatever advice he decides to seek from his colleagues.


A technical assertion on behalf of the applicant which is unsupported by published material should be in the form of sworn evidence unless the substantive examiner can confirm independently that it is correct. It should be clear who is making the assertion and what their status is. A statement attributed to a third party, whether identified or not, is hearsay evidence - see 123-18.

If the assertion runs counter to what is published, this fact should be commented on and justified. Any evidence should preferably be filed before the matter is brought to a hearing since if it is not then it is unlikely to be allowed to be filed in support of an appeal (see 101.20).

Standard of certainty, benefit of the doubt


When a prima facie objection of lack of inventive step is contested the examiner will determine the matter on the balance of the evidence available, the standard of certainty being the same pre-grant as post-grant, ie it is determined on the balance of probabilities.


An objection of obviousness should not be pursued if there is a genuine possibility that there is an inventive step. The possibility must however be real and it is far from sufficient in rebuttal of an objection that there is merely a case to be answered, or that the applicant asserts that there is doubt. The matter should be decided on the balance of the evidence available.


If the substantive examiner is unable to reach a conclusion on inventive step because of lack of technical knowledge which he cannot readily rectify and there seems a strong prima facie case that the invention is obvious, it is reasonable for the examiner to put a specific query to the applicant or to object that there is no inventive step and see what reply the applicant makes. If expert evidence would be required for him to judge whether the applicant’s reply to an objection establishes that there is invention, only then must the applicant be given the benefit of the doubt. This is consistent with the test applied in Blacklight Power Inc. v The Comptroller-General of Patents [2009] RPC 6 (see 4.02 for a case where there was substantial doubt on a question of the scientific validity of the basis of an invention. In this case, the judge held that the examiner should consider whether the evidence provided by the applicant gives rise to a reasonable prospect that, if the issue were to be fully investigated at trial with the benefit of expert evidence, it would be resolved in the applicant’s favour.

Other matters


The question of whether a claim involves an inventive step does not normally arise if the claim lacks novelty. It would be illogical to say that there is no step but that the step is non-inventive. In particular the same prior art should not be formally cited against the same claims under s.1(1)(a) and (b) simultaneously. However, in appropriate cases an objection that an invention is not new may be followed by a “fall-back” objection that if the claim were shown to be novel then it involves no inventive step. Thus the substantive examiner should investigate whether there is invention in a claim which he has objected to as lacking novelty where the novelty objection depends, for example, on a verbal coincidence or a matter of interpretation or construction and does not strike at the basic inventive concept. When a document is relevant to a lack of novelty objection against certain claims and also to an obviousness objection against other claims at the same action, it should be cited in respect of both objections. As a general rule, and subject to the above considerations, the first report under s.18(3) should refer (by formal citation or otherwise) to all the prior art documents considered to be relevant to novelty and/or inventive step (although if the documents referred to are only examples of many, that fact should be stated without listing all of the many).


The substantive examiner may also object that the claim is not clear but that so far as the claim can be understood it appears that the invention is not new, and/or does not involve an inventive step. If there is no substantial novelty objection some indication of the prima facie case for the lack of inventive step against the assumed invention should normally be given.

[RC5 should be used].

Subsection 3: Assessing obviousness


The question is, does the invention make available to the person skilled in the art something that he would not reach by normal exercise of his skill? If so, the inventor has made a contribution to the art which provides the consideration justifying the grant of a patent. The contribution must be of a technical nature. This is not to say that it must be technically complex; simplicity does not count against an invention and may indeed point to its being non-obvious. There may be invention in appreciating commercial features, for example in realising that there is a market for a new product. The Court of Appeal has provided competing views on this, see Hallen Co v Brabantia (UK) Ltd [1991] RPC 195 and Dyson Appliances Ltd v Hoover Ltd [2002] RPC 22 at 3.07.

Deciding the fourth Windsurfing/Pozzoli step


Many different approaches to deciding the fourth Windsurfing/Pozzoli step, the substantive assessment of inventive step, have been put forward over the years. What follows are discussions of some of the more prominent suggestions. The approach taken at this stage will depend upon the particular circumstances of the case under consideration.


One may also wish to consider the discussions of these and other approaches available within guides such as “Terrell on the Law of Patents” 16th (2006) Edition and the “CIPA Guide to the Patents Acts” (5th Edition). The locations of the relevant discussions in these guides are summarized in the table below.

Topic Terrell CIPA Guide
simplicity no objection 12.150 3.26
avoidance of hindsight 12.145 3.40
technical not commercial obviousness 12.18 3.33
obvious to try 12.126, 12.142 3.30
long-felt want; commercial success 7.77, 81 3.32, 3.33
right to work - 3.26
lying in the road - 3.26
“would” not “could” 12.91 3.12
if obvious, why was it not done before? - 3.34
selection 12.41, 12.188 3.31
overcoming a technical prejudice 12.55-62, 12.174-179 3.17

The Haberman questions


A number of issues should be considered in determining whether a development is obvious or not. In Haberman v Jackal [1999] FSR 685 (at 699 to 701), Laddie J considered the following non-exhaustive list of relevant questions some of which may not be answerable before grant or without evidence:

(a) What was the problem which the patented development addressed?
(b) How long had that problem existed?
(c) How significant was the problem seen to be?
(d) How widely known was the problem and how many were likely to be seeking a solution?
(e) What prior art would have been likely to be known to all or most of those who would have been expected to be involved in finding a solution?
(f) What other solutions were put forward in the period leading up to the publication of the patentee’s development?
(g) To what extent were there factors which would have held back the exploitation of the solution even if it was technically obvious?
(h) How well had the patentee’s development been received?
(i) To what extent could it be shown that the whole or much of the commercial success was due to the technical merits of the development?


In determining whether an invention is obvious in the light of a given document combined with common general knowledge, other documents, or instances of prior use, there are two major considerations: (i) whether the skilled person could reasonably be expected to find the document in conducting a diligent search for material relevant to the problem in hand see 3.26 and see 3.44) and (ii) whether, if he had found the document, he would have given it serious consideration. So far as (ii) is concerned, relevant factors may be the age of the document (see 3.37.2 and see 3.39.1) and whether, if it is one of a large number, there was any reason why the skilled person should have selected it (see 3.88). Passages which lead away from the applicant’s invention must be taken into account as well as those that lead towards it. It is relevant in looking at a prior document to consider whether the matter of interest to the obviousness question constitutes a principal feature of the prior document or whether it is mentioned merely as a detail in the performance of an entirely different concept, without any recommendation to the reader which would encourage him to use it in different circumstances.

Right to work


Just as an invention will lack novelty if the claim to it would re-monopolise something already disclosed (the so-called “post-infringement test” - see 2.03), likewise it will be regarded as obvious if a claim to it would inhibit the rights of a skilled workman to carry out routine modifications of what is already in the public domain. Just as the notion behind anticipation is that it would be wrong to enable the patentee to prevent a man from doing what he has lawfully done before the patent was granted, that behind obviousness is that it would be wrong to prevent a man from doing something which is merely an obvious extension of what he has been doing or of what was known in the art before the priority date of the patent granted (judgment of Court of Appeal in Windsurfing International Inc. v Tabur Marine (Great Britain) Ltd, [1985] RPC 59 at page 77).

Lying in the road


In Philips (Bosgra’s) Application, [1974] RPC 241 the applicants proposed to amend a claim (which had been held obvious) to a method of producing a vaccine in order to specify the use of certain emulsifying agents. The hearing officer held that the amended claim was not obvious since, although these emulsifying agents were well known, it was not certain that a notional research group would be directly led as a matter of course to try these particular agents. On appeal however, Whitford J ruled that this was not the correct question; although the skilled person would not necessarily be led directly to try these materials, they were obvious in the sense that they were lying in the road (ob via) for the worker to use, and it was wrong that he should be stopped by a monopoly from doing so. Moreover, just as it has been established that to impugn novelty, prior enabling disclosure is required, so a claim to a product will only be obvious if not only the idea of the product is obvious but also a way of producing the product is obvious (Boehringer Mannheim GmbH v Genzyme Ltd [1993] FSR 716).

Why was it not done before?

see also 3.37.2-3.39 and 3.80-3.81.2 and 3.97-3.101


The fact that no-one has followed a particular path before does not of course dispose of an obviousness objection, otherwise any invention which was new would automatically be inventive. However the reasons why this has not been done before may well be important. If the inventor has solved a long-standing problem by using in a conventional way materials or techniques which have only recently become available, then this is not inventive.


Nor is it inventive to respond to a change in economic circumstances; for example if a product has not been made from a particular material or by a particular process for reason of cost, and the material or process becomes cheaper or the market value of the product increases, it is not inventive to take advantage of this. And if a newly-arisen problem is solved by the use of available resources in an obvious way, then there is no inventive step (unless the inventor has been the first to identify the problem). But if the inventor has solved a long-recognised problem by means which others could have used but did not, then there may be an inventive step (Minnesota Mining and Manufacturing Co v Rennicks (UK) Ltd [1992] RPC 331). In Chiron Corpn v Organon Teknika Ltd [1994] FSR 202 a claim to a polypeptide comprising an antigenic determinant of the hepatitis C virus was found to be non-obvious because despite the attempts of numerous research groups over a 10 year period to identify the agent responsible for Non-A, Non-B Hepatitis (latterly named Hepatitis C), the patentees succeeded in a unique fashion by adopting a known technique which would not have been obvious to try in the circumstances.

Fulfilling a need

see also 3.37.2-3.39 and 3.78-3.79 and 3.97-3.101


Evidence that an invention fulfils a long-felt want and has been commercially successful may be taken into account in assessing obviousness (see for example Hickman v Andrews, [1983] RPC 147 and PLG Research Ltd v Ardon International Ltd, [1993] FSR 197). Aldous J held in Optical Coating Laboratory Inc. v Pilkington P.E. Ltd. [1995] RPC 145 at page 166 that while it is always important to consider why a possibly inventive step had not been suggested before, without evidence of a long-felt want or unsuccessful attempts to solve a particular problem, any evidence as to novelty, years of delay in developing the prior art and an advantage stemming from the invention carries no weight.


Moreover the commercial success of the invention may be attributable to factors achieved independently of the invention, such as the quality or price of the product, or to superior marketing. In Haberman v Jackal see 3.75 the development was a small and simple change to a “trainer cup” to make it leakproof. The new product achieved large success despite small advertising budgets and “unconsidered aesthetics” in its original version. The materials for the design had long been readily available and the advantages were immediately apparent once it was thought of. In this context, the commercial success was held to demonstrate that the invention itself fulfilled a significant long-felt want and that if the development had been obvious it would have been found by others earlier. Similarly, in Schlumberger Holdings Ltd v Electromagnetic Geoservices AS [2010] RPC 33, the Court of Appeal considered the evidence from published material at the time of the invention and held that:

The plain fact is that there was no real explanation of why the idea was not taken up well before the date of the Patent. The simplest explanation – indeed the only one that fits the known facts – is that the inventors hit upon something which others had missed.


In Tetra Molectric Ltd v Japan Imports Ltd, [1976] RPC 547 on the other hand, it was held that the commercial success of a cigarette lighter was due in large part to hammer mechanisms developed since the date of the invention; although claim 1 covered lighters which had enjoyed commercial success, it also covered lighters which could never do so, and no features which might ensure success were recited.


In Dr Reddy’s Laboratories (UK) Ltd v Eli Lilly and Co Ltd [2008] EWHC 2345 (Pat), [2009] FSR 5, the Patents Court pointed out at paragraph 187 that arguments based on commercial success of products the subject of anterior patent protection are more or less doomed to failure because the existence of that patent (application) provides a clear explanation of why no third party ever launched the product. The earlier cases of Cipla Ltd v Glaxo Group Ltd [2004] EWHC 477, RPC 43 (at [115]) and Generics (UK) Ltd v H Lundbeck A/S [2007] EWHC 1040, [2007] RPC 32 (at [251]) were referred to.

Advantages of the invention


Where a variation from published matter proposed by the applicant has no advantages, or is even disadvantageous, although it can be argued that the resulting inferior procedure is not obvious in the sense that no skilled person would regard it as obvious to do something inferior, the application should nevertheless, if the variation is one whose possibility a skilled person would appreciate, be refused on the ground that there is no inventive step. Such a view was taken by the Technical Board of Appeal of the EPO in Decision T119/82, OJEPO 5/84, see particularly paragraph 16. The position is of course different if the applicant has discovered that a variation thought to be disadvantageous is in fact not so, or if from a large number of variants which would have been regarded as no more than feasible alternatives with no advantages, the applicant has selected a variant with an unexpected advantage (see also 3.88-3.93)

Obvious to try


In Johns-Manville Corporations Patent, [1967] RPC 479 it was held that where a skilled worker in a particular field could be expected to know of a use of material to achieve a certain result in that field, an invention which is concerned with the use of that material to achieve the same result in a part of that field which had not been previously disclosed is obvious if a person versed in the art would assess the likelihood of success sufficient to warrant a trial. In more recent cases the courts have however departed somewhat from this view (see 3.87.2). The invention was concerned with the use of particular flocculating agents in asbestos cement manufacturing. It was held that, filtration processes being common to many industries, two cited documents, although addressed primarily to the mining and paper industries respectively, were likely to be read by those concerned with the asbestos cement industry, and that such readers would have realised that here was a newly- introduced flocculating agent which it was well worth trying out in their filtration process.


In Brugger and others v Medic-Aid Ltd [1996] RPC 635 Laddie J held that if a particular route is an obvious one to try, it is not rendered any less obvious from a technical point of view merely because there are a number, and perhaps a large number, of other obvious routes as well. Similarly in Bristol-Myers Squibb Co v Baker Norton Pharmaceuticals Inc [1999] RPC 253, Jacob J held that an effect which was revealed by following the obvious course of action did not make the action non-obvious.




The Court of Appeal in Saint-Gobain PAM SA v Fusion Provida Ltd and Electrosteel Castings Ltd [2005] EWCA Civ 177, [2005] IP & T 880 held that the mere possible inclusion of something within a research programme on the basis you will find out more and something might turn up is not enough to show obviousness. If it were otherwise there would be few inventions that were patentable. The cited prior art pointed to the possibility that using a Zn/Al alloy as a coating for a cast iron pipe to be buried in soil might be beneficial by showing results for this alloy coating for buried steel plates. It was not however possible for the skilled person to predict success, so the invention was not obvious. Jacob LJ held that

the ‘obvious to try’ test really only works where it is more-or-less self- evident that what is being tested ought to work.


An invention can therefore only be said to be “obvious to try” if there is a reasonable expectation of success (see also 3.99). In Angiotech Pharmaceuticals Inc’s Patent (Application for Revocation by Conor Medsystems Inc) [2006] RPC 28, the Patents Court held that the contribution to the art made by the specification had to be assessed in order to decide whether it was sufficient to show that something was an obvious candidate for testing without any expectation of success, or whether it was necessary to show that the skilled person must have had an expectation of success sufficient to induce him to use it in practice. This decision was upheld by the Court of Appeal ([2007] RPC 20) but was later overturned in the House of Lords (Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2008] RPC 28) where this distinction was rejected. Lord Hoffmann stated

…there is in my opinion no reason as a matter of principle why, if a specification passes the threshold test of disclosing enough to make the invention plausible, the question of obviousness should be subject to a different test according to the amount of evidence which the patentee presents to justify a conclusion that his patent will work.

In this case, the patent specification disclosed that taxol could be incorporated on a stent (a tubular device which acts as scaffolding to hold a diseased artery open). The prior art disclosed a very similar stent with a large range of drugs which could be incorporated on the stent to prevent restenosis. While taxol was not specifically mentioned, a range of classes, which could include taxol, were listed as possible candidates. The lower courts considered that the specification gave no suggestion that taxol would be safe or prevent restenosis (closure of the lumen of the artery caused by proliferation of smooth muscle cells) i.e. there was no disclosure that taxol would be a better candidate than any other possible candidate. Consequently a claim to a taxol-coated stent was held by the lower courts to be invalid as it was concluded to be obvious to a skilled person that taxol should be incorporated onto a stent with a view to seeing if it prevents restenosis and is safe. The House of Lords, however, held that there was evidence provided in the specification as filed that taxol was a particularly effective anti-angiogenic agent, and the invention was based on the principle that inhibition of angiogenesis could be used to prevent restenosis. The issue to be decided was therefore whether it was obvious to use a taxol-coated stent to prevent restenosis, not whether taxol was an obvious candidate for further investigation. Lord Hoffman held that the claim was not obvious and confirmed that the notion of something being obvious to try was useful only in a case where there was a fair expectation of success. How much of an expectation would be needed would depend upon the particular facts of the case. While the House of Lords accepted that the absence of any evidence to support a speculative claim could lead to an objection of lack of support or insufficiency (quoting the decision in Prendergast’s Applications), they held that this requirement should not be confused with the requirement for inventiveness.


The main issue to be decided in Omnipharm Limited v Merial [2011] EWHC 3393 (Pat) related to a claim to a “spot on” formulation for the treatment of fleas in pets, the closest prior art being a “spray on” formulation of the same active ingredient. Floyd J held that since “spot on” formulations have advantages in terms of ease of application it would be obvious to try to develop a spot on formulation; however in this particular situation the skilled team was considered to have no common general knowledge basis on which to make a prediction as to whether a “spot on” formulation would work. Therefore the skilled person would not have had sufficient expectation of success to render the invention obvious.


In Novartis AG v Generics (UK) Ltd (trading as Mylan) [2012] EWCA Civ 1623, it was held that it is important to have regard to “all the circumstances of the case including, where appropriate, whether it was obvious to try a particular route with a reasonable or fair expectation of success. What is a reasonable or fair expectation of success will again depend upon all the circumstances and will vary from case to case”. Kitchin LJ went on to hold that “it may be appropriate to consider whether it is more or less self-evident that what is being tested ought to work” and “simply including something in a research project in the hope that something might turn up is unlikely to be enough. But I reject the submission that the court can only make a finding of obviousness where it is manifest that a test ought to work. That would be to impose a straightjacket upon the assessment of obviousness which is not warranted by the statutory test and would, for example, preclude a finding of obviousness in a case where the results of an entirely routine test are unpredictable”. In Actavis Group PTC EHF v ICOS Corporation & Ors [2017] EWCA Civ 1671, it was held that a dosage of 5mg of tadalafil was obvious over prior art which stated 50mg of tadalafil was possible. The court held that a skilled team would try different doses of the drug, in a routine clinical trial, and would reach a dosage of 5mg. The judge noted that “there are some steps which can be characterised as so routine that the skilled person would carry them out simply because they are routine, and irrespective of any prospect of success. An example is routine dose ranging studies in the clinical testing of a known drug”. The court went on to say that they have “been at pains to warn against the over-elaboration of the “obvious to try” line of cases. While there are a number of factors which, depending on the circumstances, may bear on the question it is not always necessary for all of them to be ticked off as if on a checklist”. Also see Gedeon Richter v Bayer Schering [2011] EWHC 583 (Pat).


See also 2.18-2.20


Although there is no inventive step if it is clear from the prior art that taking that step is likely to lead to success, there may be invention if that is only one of many courses possible, and there is no reason to infer from the prior art that this one is more likely than the others to be profitable. In Bayer AG (Baatz’s) European Application [1982] RPC 321, carbonless copying paper was characterised by microcapsules made of a particular polymer, which was already known for forming coatings on textiles, leather, wool and metal. Even if these were thought to be neighbouring fields, there was no reason to expect that improved results would be obtained by the use of this material (as the results of comparative experiments showed they were), and thus it was not obvious to select it from the enormous number possible. And in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd, [1970] RPC 157 at page 192, it was held not to be obvious that a useful drug would be obtained by substituting -CF3 for -Cl in a known drug, given the large amount of prior material, leading in a number of different directions, which was before the skilled person at the date of the invention.


When faced with claims that may relate to a selection invention the prima facie inventive step objection should be raised using the Windsurfing/Pozzoli approach, unless the selection is so clear-cut as to make this unnecessary. If the applicant/agent maintains (or it is clear from the specification) that the inventiveness may lie in a selection invention, then the approach used by the Court of Appeal in Dr Reddy’s Laboratories (UK) Ltd v Eli Lilly & Co Ltd [2010] RPC 9 should be followed. In such cases, the question to be asked is whether the invention makes a hitherto unknown technical contribution or is merely an arbitrary selection. If it is merely an arbitrary selection then the invention is obvious. In Generics [UK] LTD (t/a Mylan) v Yeda Research and Development co. LTD & Anor [2013] EWCA Civ 925 the Court of Appeal considered the law regarding selection inventions, with reference to Dr Reddy’s and the EPO Board of Appeal decision in T 939/92 AGREVO/Triazoles 6 OJEPO 309. The position following the judgment in Generics is as follows:

i) Article 56 of the EPC is in part based on the underlying principle that the scope of the patent monopoly must be justified by the patentee’s contribution to the art;

ii) If the alleged contribution is a technical effect which is not common to substantially everything covered by a claim, it cannot be used for the purposes of judging obviousness;

iii) In such circumstances the claim must either be restricted to the subject matter which makes the technical contribution, or a different contribution common to the whole claim must be found;

iv) A selection from the prior art which is purely arbitrary and cannot be justified by some useful technical property is likely to be held to be obvious because it does not make a real technical advance;

v) A technical effect which is not rendered plausible by the patent specification may not be taken into account in assessing inventive step;

vi) Later evidence may be cited to support a technical effect made plausible by the specification;

vii) Provided the technical effect is made plausible, no further proof of the existence of the effect is to be demanded of the specification before judging obviousness by reference to the technical effect put forward.




The Court of Appeal in Dr Reddy’s Laboratories (UK) Ltd v Eli Lilly & Co Ltd disregarded the criteria set out in IG Farbenindustrie AG’s Patents 47 RPC 289. In Dr Reddy’s Jacob LJ stated that as these rules related to pre-1977 law they could be regarded:

as part of legal history, not as part of the living law.


Patent Act s.118 refers

The hitherto unknown technical effect (i.e. advantage gained or disadvantage avoided) relied upon to justify a selection invention should be clearly identified or otherwise made plausible (e.g. discernible from tests provided in the application), in the specification at the time of filing (see also T 1329/04 Johns Hopkins University School of Medicine/Growth Differentiation Factor [2006] EPOR 8). Later-filed evidence may be used to provide support for the presence of such an effect or the fact that it is common to everything claimed, but unexpected bonus effects not described in the specification cannot form the basis of a valid claim to a selection invention (see Glaxo Group Ltd’s Patent [2004] RPC 43). If there is no statement of advantage in the specification at the time of filing it may not be added later, since, as stated by Jacob J. in Richardson-Vicks Inc.’s Patent [1995] RPC 568 at 581, in the context of synergy, whether or not the advantage was demonstrated

by experiments conducted after the date of the patent cannot help show obviousness or non-obviousness … and it would be quite wrong for later-acquired knowledge to be used to justify the amended claim.


The judgment in Generics [UK] LTD (t/a Mylan) v Yeda Research and Development co. LTD & Anor [2013] EWCA Civ 925 also addressed the question of what happens if the technical property or effect made plausible by the specification does not exist in fact. The lower court had held that since later evidence cannot be used to support a technical effect not indicated in the specification, neither can it be used to refute such an effect. The Court of Appeal held however that in considering later evidence on this issue one is not judging the obviousness of the invention by reference to later evidence; one is simply defining by evidence what the invention is. The Judge allowed the admission of later evidence which, according to Mylan, showed that the composition as claimed did not demonstrate the relied upon technical effect. The Judge however found that the evidence provided did not prove the absence of the technical effect and rejected the appeal.


Although the size of the class from which a member or members have been chosen is not relevant to the question of novelty of a selection invention, it may be relevant to the question of obviousness (Du Pont de Nemours &c (Witsiepe’s) Application, [1982] FSR 303 at page 310), see 2.19 – 2.20.


The technical significance of the parameters by which the product or process is selected should be considered. Where unusual parameters are used in a claim it may be difficult to prove whether or not the prior art would have inevitably exhibited those parameters, but in Raychem Corp.’s Patents [1998] RPC 31 it was held (at pp.46-47) that:

although it may not be obvious, in the common use of that word, to limit a claim by reference to some particular meaningless and arbitrary parameter, that had nothing to do with patentability. Patents are not given for skill in inventing technically meaningless parameters.

If a product or process with obviously desirable characteristics happens to fall within the limits of such claims then they cover what is obvious and will thus be invalid.

Additional advantage not inventive


Although the discovery of an unexpected advantage may point to a step not being obvious if it was only one of many steps which could have been tried (see 3.88) or if it was one taken counter to accepted views (see 3.97), if the prior art leads directly to the step then it is not made inventive by any additional advantage obtained. In Inventa AG’s Application, [1956] RPC 45, the use for spinning nylon of a process which had been disclosed (before the introduction of nylon) for spinning artificial filaments in general was held to be obvious, and not to be saved by an additional advantage, since no further modification of the process was required to secure this advantage. And in Union Carbide Corporation (Hostettler’s) Application, [1972] RPC 601 at page 609, Whitford J observed (obiter) that

if in fact the step taken was an obvious step, it remains an obvious step however astonishing the result of taking it may be.


An added benefit, however great, will not found a valid patent if the claimed innovation is obvious for another purpose (judgment of the Court of Appeal in Hallen Co v Brabantia (UK) Ltd [1991] RPC 195). In Hallen, it was held to be obvious to coat a corkscrew of self-pulling type with PTFE to facilitate its penetration into a cork; the claimed invention was not saved by the non-obvious additional advantage of facilitating extraction of the cork from the bottle (although it might have been saved as a selection patent if the specification had contained clear assertions that the corkscrew in question turned the use of PTFE to special advantage over other corkscrews in the extraction stage, thus overcoming a problem of all previous self-pullers).


In general, an otherwise obvious combination is not saved from a finding of obviousness by some unexpected advantage caused by an unpredictable co-operation between the elements of the combination (see Glaxo Group Ltd’s Patent [2004] RPC 43).

Overcoming a technical prejudice


An invention may be regarded as non-obvious if it goes against the generally accepted views and practices in the art. As the Patents Court in Dyson Appliances Ltd v Hoover Ltd [2001] RPC 26 made clear (upheld by the Court of Appeal [2002] RPC 22), the common general knowledge held by the skilled person may have both positive and negative aspects, and it is necessary to take account of both; in other words to take account of what the skilled person would consider doing and what the skilled person would be prejudiced against doing, as a result of that knowledge. If the common general knowledge was such that the skilled person did not perceive a problem with the prior art, it becomes “considerably more difficult” to establish the obviousness of taking a particular step which would bring that prior art within the scope of the claims in question. In the case in question it was held that the common general knowledge of the skilled person at the relevant time, along with a lack of a perceived problem, would mean that the skilled person would never have considered using anything other than bag technology in a vacuum cleaner. Further examples are if persons skilled in the art would regard certain materials or techniques as unsuitable for a particular purpose, then if the inventor has found that this prejudice is not well-founded, then he has made an inventive contribution to the art. A patentee who advances the art by showing that, contrary to the prevailing view, the idea will work or is practical has shown something new and inventive (see Pozzoli SPA v BDMO SA [2007] EWCA Civ 588. Likewise the omission of a step hitherto thought to be necessary may constitute an inventive step.


It must however be clear that the technical prejudice which the applicant claims to have overcome did in fact exist, and that it was not justified. A prejudice which is insufficiently widespread for it properly to be regarded as commonly shared should not be attributed to the notionally skilled person. In Glaxo Group’s Patent [2004] RPC 43, it was held that a prejudice does not exist if some people engaged in the art laboured under a particular prejudice if a substantial number of others did not. Thus a rooted objection to the regular use of b2-antagonists in the treatment of asthma, which was the subject of an ongoing dispute amongst specialist physicians, was not ascribed to the skilled person. Another situation is where scientific opinion is out of accord with what is done in the market, as occurred in Ancare New Zealand Ltd’s Patent [2003] RPC 8 for a sheep drench comprising two known agents, one active against roundworms and one active against tapeworms. Here, the patentee argued that an inventive step lay in including the tapeworm agent because there was scientific hostility against treating tapeworms in sheep. However, it was common practice for New Zealand farmers to treat their lambs for tapeworm at the priority date. The Privy Council, upholding judgments of the New Zealand High Court and Court of Appeal to revoke the patent for obviousness and not involving any inventive step over what was known or used before the priority date of the claim in New Zealand, held that:

the fact that scientific opinion might have thought that something was perfectly useless did not mean that practising it, or having the idea of making a preparation to do it, was an inventive step. Otherwise, anyone who adopted an obvious method for doing something which was widely practised but which the best scientific opinion thought was pointless could obtain a patent.


For an invention to overcome a technical prejudice, and therefore be non-obvious, a genuine prejudice must exist which would have prevented the skilled person from taking the step that would lead to the claimed invention. In Teva UK Ltd and others v AstraZeneca AB [2012] EWHC 655, the patent claimed a sustained release formulation of a drug, quetiapine, for the treatment of schizophrenia. AstraZeneca, the patent holder, argued that there were technical considerations preventing the skilled person from considering developing a sustained release formulation of quetiapine, so called “lions in the path”, and therefore the patent was inventive. They argued that the skilled team in light of the prior art would be deterred from considering a sustained release formulation because quetiapine is rapidly metabolized by the liver (see also 3.83-3.87.1). The claimants however, argued that it would be obvious to formulate quetiapine for sustained release and that the alleged prejudices against doing so were illusory, mere “paper tigers”. The judge held that an immediate release once-daily formulation would not be efficacious without increasing the dose and therefore there was rationale for the skilled person to seek a sustained release formulation. The judge also held that on the evidence quetiapine is not metabolised in a way which would deter the skilled person from attempting a sustained release formulation. Accordingly AstraZeneca’s patent was held to be obvious and was revoked. In [Actavis UK Ltd v Novartis AG [2010] EWCA Civ 82]( a claim to a sustained release formulation for the drug fluvastatin was also held to lack an inventive step since the obstacle put forward in the patent against being able to make such a formulation was illusory.


There is also no invention in merely tolerating the disadvantages which have deterred others. For example if an inexpensive plastics material is thought unsuitable for making tools because it is not durable, there is no invention in using it to make a cheap screwdriver intended only for light work and accepting that it will have only a short life.


Some of these points may be illustrated by a hypothetical example. Suppose that it has been stated for years in textbooks that a particular class of chemical reaction carried out under elevated pressure, gives poor yields, and an inventor now claims the synthesis of a particular compound by such a process. If all he has done is take advantage of the high price commanded by the product, or the cheapness of the starting materials, and has decided to accept the disadvantage of low yield, then that is not inventive; it is an obvious response to prevailing economic circumstances. On the other hand, if the inventor has discovered that good yields can be obtained by the use of still higher pressures, a fact not suggested in the prior art, then that would be inventive. But if higher yields would be expected at difficult-to-obtain pressures, and the inventor has merely taken advantage of new techniques making such pressures more available, then that is not inventive. Finally, if the inventor has discovered that the standard accepted views on the low yields, while being normally true for this reaction, are not in fact true for this particular compound, then there is inventive step in the choice of this process.