Manual of Patent Practice

Section 64: Right to continue use begun before priority date

Sections (64.01 - 64.06) last update October 2012.


Under this section, a person has rights to continue an act which he did or prepared to do before the priority date of an invention and which would otherwise be an infringement of a patent for the invention. The recipients of products disposed of in exercise of such rights are protected by subsection (3).


For the applicability of s.64 in relation to European patents, see 60.02.


The wording of section 64 generally corresponds to that of subsections (4) to (6) of section 28A, both being concerned with protecting the rights of third parties who take steps which would have constituted infringement of a patent if that patent had been in force at the time.

Section 64(1)
Where a patent is granted for an invention, a person who in the United Kingdom before the priority date of the invention

(a) does in good faith an act which would constitute an infringement of the patent if it were in force, or

(b) makes in good faith effective and serious preparations to do such an act, has the right to continue to do the act or, as the case may be, to do the act, notwithstanding the grant of the patent; but this right does not extend to granting a licence to another person to do the act
Section 64(2)  
If the act was done, or the preparations were made, in the course of a business, the person entitled to the right conferred by subsection (1) may -

(a) authorise the doing of that act by any partners of his for the time being in that business, and

(b) assign that right, or transmit it on death (or in the case of a body corporate on its dissolution), to any person who acquires that part of the business in the course of which the act was done or the preparations were made


The way in which a person acquires rights under this section is to perform a potentially infringing act or make “effective and serious preparations” to do so, before the priority date of the invention. The priority date is determined for each individual invention in accordance with s.5 and may differ for different matter in the same patent, see 5.20 to 5.25.

The performance or preparations must be in the UK and “in good faith”. In Lubrizol Corporation v Esso Petroleum Co. Ltd. [1998] RPC 727 the Court of Appeal affirmed (at page 770) that the protection afforded by the section to the prior user is not strictly limited to acts identical to those which were performed before the priority date but “cannot be a right to manufacture any product, nor a right to expand into other products”. Jacob J’s statement in the Patents Court was upheld that “if the protected act has to be exactly the same (whatever that may mean) as the prior art then the protection given by the section would be illusory.

The section is intended to give practical protection to enable a man to continue in substance what he was doing before.” In the event, two customer trials by the defendant in the UK of small samples imported from the US with a view to possible later manufacture in the UK but with no decision yet made, were held, although serious, not to be “effective” preparations to do an infringing act. Brooke LJ (at page 785) amplified that it is not “sufficient to show that the serious preparations, if pursued to finality, will have the requisite effect.” In the Patents Court ([1997] RPC 195), Jacob J also pointed out that in deciding whether an activity is substantially the same as the prior act, both technical and commercial matters must be taken into account, but there should be no account taken of how the patentee may have chosen to cast his monopoly. Furthermore, it was noted obiter that although the decision was governed by Section 64 as it stood prior to amendment by the CDP 1988, the amendment would not make any difference if it were applicable.


Although this section makes no distinction between public and secret acts, if the act was public it might constitute prior disclosure of the invention whereby it became part of the state of the art under s.2(2), thus depriving the invention of novelty and impugning the validity of the patent (see 2.27 to 2.29). If the patent was thus invalid, infringement would not arise and a user would not need the protection of s.64.


The rights resulting from such an act, or preparations therefor, prior to the priority date are that the person can continue to do, or do, that act without infringing the patent in question. He cannot grant a licence to any other person to do that act but, if the prior act or preparations occurred in the course of a business, he can assign or transmit the right to do it or authorise it to be done by a partner as set out in subsection (2).

Section 64(3)
Where a product is disposed of to another in exercise of the rights conferred by subsection (1) or (2), that other and any person claiming through him may deal with the product in the same way as if it had been disposed of by the registered proprietor of the patent.