Economic note 1052: counter terrorism (accessible)

Question 1

Summary Table: Measures included in “Counter Terrorism”.

Accepted Answer

Youth Diversion Order

Measures included:

Introducing a new youth diversion order to disrupt young people (aged 21 years and under) involved in terrorism-related offending, and divert them from the wider criminal justice system (CJS), including prosecution, given a lack of effective existing tools.
The order would impose both restrictive and supportive measures on the young person to reduce the risk the individual poses and support them away from terrorist ideologies.

Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

Measures included:

Amending the Terrorism Prevention and Investigation Measures Act 2011 to broaden the definition of weapons.
This will support the police and Security Service to manage the risk from those involved in terrorism related activity, by limiting access to bladed articles and other articles capable of being used as a weapon.
As part of this same measure, an equivalent amendment will also be made to the State Threats Prevention and Investigation Measures regime.

Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

Measures included:

Amending section 13(1) of the Terrorism Act 2000 to enable the police to seize any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed organisation.
Currently the seizure powers are dependent on the article being used in criminal proceedings.

Application of certain terrorism offences (wearing of uniform /displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

This measure widens the application of the existing offence in section 13(1) of the Terrorism Act 2000 to prisons as well as other prescribed places of detention or residence.
The section 13(1) offence criminalises the display or wearing of articles in public places, such as images or uniform, which would arouse a reasonable suspicion that the individual is a supporter or a member of a proscribed organisation.

Management of historic terrorist-connected offenders

Introducing a new power for the police, or the Secretary of State for the Home Department (Home Secretary), to apply to the courts to permit specific counter terrorism risk management tools to be applied to a small number of offenders that the government believes would have been determined by the court as having a ‘terrorist connection’ if this label had been available at the time of their sentencing (mainly before 2009).

Economic Note: Number: HO EN 1052

Title of regulatory proposal: Crime and Policing Bill: Counter Terrorism and National Security Measures

Lead Department/Agency: Home Office

Expected date of implementation:

Youth Diversion Orders: October 2026
All other measures: July 2026

Origin

Date: 17/02/2026

Lead Departmental Contacts: CrimeandPolicingBillTeam@homeoffice.gov.uk

Departmental Assessment: Green

Question 2

Rationale for intervention, objectives and intended effects.

Accepted Answer

These measures make changes to counter terrorism legislation to ensure law enforcement and intelligence agencies have the powers they need to keep the public safe. These measures will:

Introduce a new tool for the police to intervene earlier in counter terrorism cases involving young people, reducing the risk of young people being prosecuted for terrorism offences.
Make limited changes to police powers to disrupt terrorism related activity and improve management of terrorist offenders.
Extend an existing terrorism offence to reduce the risk of the prison estate being a permissive place for radicalisation.

These measures are supported by operational partners and the Independent Reviewer of Terrorism Legislation.

Question 3

Policy options (including alternatives to regulation)

Accepted Answer

Option 0: ‘Do nothing’ – continuation of current regulatory regime.

Option 1: legislate for -

Measure 1A: Youth diversion order.
Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.
Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.
Measure 1D: Application of certain terrorism offences (wearing of uniform /displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.
Measure 1E: Management of historic terrorist-connected offenders.

Option 1 is the government’s preferred option as it meets the policy objectives

Question 4

Costs and benefit summary

Accepted Answer

The preferred option incurs various costs including device installation and support, deradicalisation, subject monitoring, familiarisation, and resourcing for the prison services, CJS and operational partners.

Benefits include reduced prison pressure, operational savings in managing security risks, efficiency savings and various other non-monetised security benefits.

Question 5

Risks

Accepted Answer

Any considerable changes to the proposed volumes of affected individuals or their behaviour would pose an analytical risk. Furthermore, proxies have been used to model costs where actual costs could not be sourced. Mitigations are in place for these risks.

Total Cost (£m PV)	Transition Cost (£m Constant)	Cost to Business (£m PV)
Omitted	0.2	0.0
Total Benefit (£m PV)	NPSV (£m PV)	BNPV (£m PV)	EANDCB (£m PV)
Omitted	-13.52	0.0	0.0
Price Base Year	PV Base Year	Appraisal period (Years)	Transition period (Years)
2026/27	2026/27	10	1

Departmental sign-off (SCS): Lee Dobinson, date: 26/02/2026

Chief Economist sign-off: Tim Laken, date: 24/03/2026

Better Regulation Unit sign-off: Emma Kirk, date: 24/03/2026

Question 6

Evidence Base

Accepted Answer

A. Policy objectives and intended effects

Measure 1A: Youth diversion order

1. Introducing a new youth diversion order (YDO) to implement and build on a recommendation from the Independent Reviewer of Terrorism Legislation (IRTL) to introduce a new diversionary civil order to better manage terrorist risk from young people while reducing the need for further involvement in the CJS. A YDO would impose both restrictive and supportive measures on the young person to reduce the risk the individual poses and support them away from terrorist ideologies, decreasing the risk of further involvement in the CJS. It will be a criminal offence to breach the conditions of the order.

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

2. Amending the Terrorism Prevention and Investigation Measures Act 2011 (TPIM 2011) to broaden the definition of weapons. This will support the police and Security Service to manage the risk from those involved in terrorism related activity, by limiting their access to bladed articles and other articles capable of being used as a weapon. As part of this same measure, an equivalent amendment will also be made to the State Threats Prevention and Investigation Measures (STPIM) regime introduced by the National Security Act 2023 (NS 2023). These changes build on a recommendation made by the IRTL in his Annual Report on the Terrorism Acts in 2022.^{[footnote 1]}

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group

3. Amending section 13(1) of the Terrorism Act 2000 (TACT 2000) to enable the police to seize any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed organisation. Currently the seizure powers are dependent on the article being used in criminal proceedings. The measure will ensure that the police can remove articles from public places even where those items are not connected to an individual, without the need for the article to be used in criminal proceedings. This implements a recommendation from the IRTL’s Annual Report on the Terrorism Acts in 2022.^{[footnote 2]}

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

4. This measure widens the application of the existing offence in section 13(1) of the TACT 2000 to prisons as well as other prescribed places of detention or residence. The section 13(1) offence criminalises the display or wearing of articles in public places, such as images or uniform, which would arouse a reasonable suspicion that the individual is a supporter or a member of a proscribed organisation. This implements a recommendation from the IRTL’s report on Terrorism in Prisons published in 2022^{[footnote 3]}, following terrorist attacks committed by serving prisoners or terrorist offenders released on licence from prison such as those at HMP Whitemoor^{[footnote 4]}, Fishmongers’ Hall^{[footnote 5]}, and in Streatham^{[footnote 6]}.

Measure 1E: Management of historic terrorist-connected offenders

5. Introducing a new power for the police, or the Secretary of State to apply to the courts to permit specific counter terrorism risk management tools to be applied to a small number of offenders that the government believes would have been determined by the court as having a ‘terrorist connection’ if this label had been available at the time of their sentencing (mainly before 2009).

B. Policy options considered, including alternatives to regulation

6. There are two options:

Option 0: ‘Do nothing’

7. The Home Office do not consider that this is a feasible option given that it is essential counter terrorism legislation is fit for purpose and ensures operational partners have the powers they need to protect the public. A main aspect of this is considering recommendations and feedback from operational partners on the evolving threat from terrorism, and recommendations made by the IRTL, who has a statutory duty to review the operation of the Terrorism Acts and other counter terrorism legislation. The measures in Option 1 (legislate) are all provisions which are supported by operational partners and/or the IRTL.

Option 1 - legislate for -

Measure 1A: Youth diversion order.
Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.
Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.
Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.
Measure 1E: Management of historic terrorist-connected offenders.

8. Across these measures, the need for legislative change has been identified by operational partners and/or the IRTL. Many of the changes are amending existing legislation and as such non-legislative approaches are not possible. It is concluded that, across the measures above, legislative change is required to fulfil the policy objectives.

Option 1 is the government’s preferred option as it meets the policy objectives.

C. Past evaluations and rationale for government intervention

7. The physical threat of terrorism can cause serious injury and death for UK citizens. Beyond the physical and emotional impact of terrorism on victims and their families, terrorism causes wider economic damage through the fear caused by terrorism. This disruption through the fear caused by terrorism has economic and social ramifications through its impact on people being unable to go about their day to day lives.

8. This is why CONTEST^{[footnote 7]} includes the aim to “reduce the risk to the UK and its citizens and interests overseas from terrorism, so that people can go about their lives freely and with confidence”. The below measures aim to provide legislative tools for law enforcement to manage the risk posed by terrorist actors.

Measure 1A: Youth diversion orders.

9. Young people comprise an increasing proportion of counter terrorism investigations. The Director General of Security Service highlighted recently that those aged under 18 now comprise 13 per cent of individuals under investigation by Security Service as of October 2024, representing a threefold increase since January 2021^{[footnote 8]}. The numbers of arrests and convictions of young people for terrorism, or terrorism related offences, have also increased, though these likely underestimate the scale of problematic activity that falls below the prosecution threshold. Most of the convictions are for online activity that constitutes offences under section 2 of the TACT 2006 (dissemination of terrorist publications) and section 58 of the TACT 2000 (collection of information).

10. The IRTL raised similar concerns about the rising number of young people (specifically children) in counter terrorism casework in his annual report on the operation of the Terrorism Acts in 2021, which led to his recommendation that the government consider introducing a new “child violence diversion order”^{[footnote 9]}. More recently, the IRTL has publicly called for alternative options to manage young people being investigated for terrorism offences.

11. Operational partners have highlighted that whilst there are existing tools to mitigate terrorist risk, they are not well designed for young people. Where terrorist risk escalates Counter Terrorism Policing (CTP) have highlighted that, whilst they may want to divert the young person away from the CJS, there is often no choice but to rely on criminal processes and outcomes as a means of risk management. As a result, operational partners support the introduction of a new youth-centred tool which could be implemented without requiring a young person to enter the CJS or admit to an offence. This would reduce the risk of a young person being prosecuted for a terrorism offence, which, in many cases, can have disproportionately negative consequences on their life chances.

12. Officials from the Home Office worked with operational partners, the Ministry of Justice (MoJ), and Devolved Governments to consider the utility of existing interventions (such as TPIMs and Youth Conditional Cautions (available in England & Wales)). The conclusion from this assessment was that whilst existing tools do provide some risk management intervention, there is no risk management tool available which has been specifically designed for the needs of young people whilst also tailored to mitigating terrorist risk, which can present different challenges to other types of criminality. For example, some tools are voluntary, which, whilst preferable, may not always be effective for individuals who are not willing to comply, others do not cover the same types of activity that would be covered by the YDO, and others have limited, or no, safeguards for young people.

13. Home Office officials have since worked with operational partners, the MoJ, the Youth Justice Board, and Devolved Governments to develop the model for the YDO, including the range of activity that would fall within scope of a YDO, the potential measures under the order, the means of monitoring compliance with the measures and appropriate safeguards governing the tool’s use. The measures that could be imposed under a YDO would include restrictions on association with specific individuals or groups (offline or online), mandatory engagement with ideological mentors, or restrictions on accessing specific websites or online apps.

14. New legislation would introduce a new power for police to apply to the courts for a YDO for cases involving individuals aged 21 and under, if specific grounds were met and the courts considered it necessary and proportionate to manage the risk from the individual. Subsequent statutory guidance would help practitioners in the application for and implementation of a YDO.

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

15. The TPIM 2011 supports the management of those involved in terrorism related activity who cannot be prosecuted or deported to prevent them carrying out further terrorist related activity. Schedule 1 to the TPIM 2011 sets out the measures which may be imposed should a TPIM be imposed. These measures include a weapons and explosives measure which prohibits owning, for example, guns, offensive weapons or explosives.

16. The TPIM 2011 does not allow the prohibition of the possession of bladed articles or other articles capable of being used as a weapon, instead only where this would be defined as an ‘offensive weapon’. An offensive weapon is defined as “an article made or adapted for use for causing injury to the person or intended by the person in possession of it for such use (by that person or another)”.

17. These changes build on a recommendation made by the IRTL, in his 2022 review on the operation of terrorism legislation in relation to TPIMs.^{[footnote 10]}

18. STPIMs were introduced by the NS 2023 and replicate the TPIM regime with a focus on preventing an individual’s further involvement in foreign power threat activity, as defined at section 33 of the NS 2023.^{[footnote 11]}

19. The TPIM 2011 will be amended to support the police and Security Service to manage the risk from those involved in terrorism related activity, by broadening the definition of weapons within the Act. This will better support restricting TPIM subjects’ access to weapons and other articles capable of being used as a weapon. An equivalent amendment will also be made to the STPIM regime.

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

20. Section 13 of TACT 2000 makes it an offence to wear any uniform, or wear, carry or display an article (including publishing images online), in a way which would arouse reasonable suspicion that the individual is a supporter or member of a proscribed organisation. The offence is an important disruption tool in countering support for proscribed organisations, particularly in a public order setting.

21. The Counter Terrorism and Border Security Act 2019 made changes to provide a bespoke power to seize articles covered by section 13. This was required as existing seizure powers were dependent upon arrest, and arrest is not always the most suitable disruptive option where a section 13 offence has occurred. For example, in a public order context this may inadvertently escalate the situation.

22. In his annual report on the Terrorism Acts in 2022, the IRTL highlighted a particular issue with the seizure powers in a Northern Ireland (NI) context, as the police must consider it necessary to seize the article to prevent any evidence associated with criminal proceedings from being concealed, lost, altered or destroyed. The IRTL highlighted that articles which may arouse support for proscribed organisations may appear in public places with no connection to a specific individual, for example, the IRTL mentions the example of flags being displayed on lampposts in NI.

23. As a result, the police may be unable to use the current section 13 seizure powers to remove these articles, as there would be no prospect of a section 13 prosecution against any individual and the purpose of the seizure is more likely to be to prevent the ongoing display which can cause harm to communities.

24. This measure will make changes to the existing seizure powers in section 13 to ensure the police can seize section 13 articles displayed in public places even where there is no reasonable prospect of prosecution. Home Office officials have engaged with the Northern Ireland Office, the Police Service of Northern Ireland (PSNI) and CTP on this measure and, whilst the Department does not consider that this will result in a significant uplift in seizures by the police, all stakeholders are supportive of making this change to improve the flexibility of the seizure power.

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.

25. Part 2 of TACT 2000 provides a regime under which certain organisations are proscribed. Section 13(1) of TACT 2000 makes it an offence to wear the uniform of a proscribed organisation, or to display items or articles that are associated with a proscribed organisation, such as the organisation’s flag.

26. Section 13(4) to (6) of TACT 2000 confer powers on a constable to seize articles, including items of clothing, that are reasonably suspected to be evidence that the section 13(1) offence has been committed.

27. The offence under section 13(1) of TACT 2000 can be committed only in a public place. Section 121 of TACT 2000 defines a public place as “a place to which members of the public have or are permitted to have access, whether or not for payment”. Under this definition a prison etc would not be considered a public place and as such the section 13(1) of TACT 2000 offence does not apply in these settings currently.

28. In April 2022, a review of Terrorism in Prisons in England and Wales produced by the IRTL was published. One of the recommendations was to amend section 13 of TACT 2000 to extend the section 13(1) offence to the prison setting^{[footnote 12]}. This measure will implement this recommendation.

29. This measure will ensure that the section 13(1) offence is capable of being committed in the settings listed below:

Prisons
Young offender institutions
Secure schools
Secure training centres
Approved Premises^{[footnote 13]}
Relevant military detention facilities
Immigration Removal Centres.

Measure 1E: Management of historic terrorist connected offenders.

30. Part 4 of the Counter Terrorism Act 2008 (CTA 2008) introduced a requirement for courts to consider whether specified non-terrorism offences were committed with a terrorist connection. If the court determines this was the case, then it must aggravate the sentence and state in open court that the offence has been aggravated.

31. Specified non-terrorist offences were those listed in Schedule 2 to the CTA 2008, that the judge considered had or may have had a terrorist connection, and which were committed on or after its date of commencement of 18 June 2009. Following the attacks at Fishmongers’ Hall and Streatham in November 2019 and February 2020 respectively, the Counter Terrorism and Sentencing Act 2021 expanded this requirement so that the court must consider whether there was a terrorist connection for all offences with a maximum penalty of more than two years’ imprisonment.

32. The CTA 2008 also introduced notification requirements for individuals with convictions for terrorism offences or offences with a terrorist connection, to notify certain information to the police and to keep that information up to date (such as their name, address, and national insurance number). For offenders with a terrorist connection, constables have the power to:

Arrest and detain a terrorist offender or a terrorist connected offender on suspicion of a breach of licence conditions, pending a decision on whether or not to recall the person to prison, if considered necessary to protect the public.
Stop and search a terrorist offender or terrorist connected offender who is released on licence. The power applies if it is a condition of the offender’s licence that they submit to a search, and the constable considers that the search is necessary to protect the public.

33. There is currently no provision to add notification requirements and the powers of arrest and personal search to the licence of an offender who committed a terrorism connected offence before the commencement of the CTA 2008 on 18 June 2009 or who committed a terrorism connected offence between 2009 and 2021 which fell outside the then specified list in Schedule 2 to the CTA 2008.

34. This measure will amend Part 4 of the CTA 2008 to allow the police or the Secretary of State to apply to the court for a notification order on an offender where an offender was sentenced before the commencement of the CTA 2008 on 18 June 2009 or between 2009 and 2021 for an offence which fell outside the then specified list in Schedule 2 to the CTA 2008. Offenders will be subject to the conditions and requirements listed in paragraph 32.

D. Appraisal

35. As the equivalent annual net direct costs to the public sector are less than +/- £20 million, an Impact Assessment is not required for this intervention and an Economic Note (EN) has been prepared instead.

36. This EN summarises the impact of the above legislative measures on individuals and groups in the UK. The costs and benefits of each legislative measure are compared to the ‘Do nothing’ option. These impacts have been assessed using HM Treasury Green Book guidance. To make the estimates for each measure comparable, the following conventions are adopted across the measures:

Monetised costs and benefits are stated in 2026/27 prices.
The Net Present Cost (NPC) and Net Present Benefit (NPB) of each measure has been calculated for a 10-year period starting in 2026/27. Present value costs are discounted to a 2026/27 base year.
A discount rate of 3.5 per cent is used when calculating economic costs.
Costs are rounded to the nearest hundred pounds.
Ranges are used, where appropriate, to account for uncertainty in the modelling.
Data from the Home Office, MoJ, Office for National Statistics, Youth Justice Board, Magistrates Association, CTP and Operational Partners are used in this analysis.
The annual cost of holding an individual in prison for a year is estimated to be £57,200 in 2026/27 prices. Annual prison and probation costs are assumed to be spread uniformly across the year.
Prisoners are assumed to start their sentences concurrently at the start of the year.
The Readingsoft^{[footnote 14]} calculator is used in calculating familiarisation costs. To calculate the cost of familiarisation, the estimated reading time of the information document was multiplied by the labour cost and the volume of individuals required to read it.
Familiarisation costs are estimated using the formula:

reading time x median wage x number of readers x (1 + (non-wage labour uplift))

In areas where explicit labour costs cannot be sourced, estimated labour costs have been calculated by applying a non-wage labour uplift of 22 per cent to public sector profession salaries, as taken from the ONS Index of Labour Costs per Hour^{[footnote 15]}.
Familiarisation costs are only incurred in Year 0 of implementation.
Where costs and inputs are not explicitly known, suitable proxies have been used and scrutinised to ensure appropriateness.

Option 1

37. These measures will result in a range of costs and benefits. The monetised costs are summarised below. It has not been possible to monetise all presented benefits due to the absence of suitable data. These measures are expected to produce the following non-monetised security benefits:

The diversion of young people away from the CJS where possible.
The prevention of TPIM subjects from possessing offensive weapons.
A reduced influence of proscribed organisations in public places.
The prevention of prisons from becoming permissive places for radicalisation.

38. By managing the risk posed by terrorism, this legislation may prevent terrorist activity (including violent attacks) that may impact British citizens and their assets and reduce the disruption of terrorism related fear which has economic and social ramifications. Due to the difficulties in estimating the future nature and scale of terrorism, it is not possible to calculate a realistic reduction in terrorism as a direct result of these policy measures.

Summary table: per-measure central values (£m) rounded to two decimal places (2026/27 prices)

Measure	Net Present Benefits	Net Present Costs	Net Present Social Value
Measure 1A: Youth Diversion Order	Have been omitted due to operational sensitivity.	Have been omitted due to operational sensitivity.	- 12.83
Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon	0.00	0.20	- 0.20
Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.	0.00	0.00	0.00
Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.^{[footnote 16]}	0.00	0.02	- 0.02
Measure 1E: Management of historic terrorist-connected offenders	0.00	0.47	- 0.47

Source: Home Office, own estimates 2026

39. See below for more detailed breakdown of the appraisal process for these measures. It should be noted that there may be other consequences of this legislation that have not been identified.

Measure 1A: Youth Diversion Orders

40. For reasons of operational sensitivity, the volume of individuals expected to be issued a YDO cannot be disclosed. Consequently, only the 10-year NPSV of the measure is presented in the summary table.

41. This measure will commence by regulations, so costs are expected to begin to be incurred from late 2026. The earliest expected date of implementation is October 2026; costs are therefore assumed to only be incurred for the latter six months of the financial year 2026/27. Ongoing costs occurring in the first year are therefore half of subsequent years. Transition costs are incurred in full.

Measure 1A: Assumptions

42. The following assumptions have been used for the analysis of this measure:

The YDO will be applicable to juveniles and young adults. The split between those aged under 18 years and those aged 18 to 21 years is expected to remain constant throughout the 10-year appraisal period. The Home Office has assumed that there is an approximate 50 per cent split between those aged under 18 years and those aged 18 to 21 years who will receive YDOs. This is based on the historic demographic split for arrests of terrorism related offences. The relevance of this split is due to the difference in prison running costs across cohorts, as it is assumed that those aged under 18 years will be sent to Youth Offender Institutions (YOIs), while those aged over 18 years will be sent to adult prisons.
Operational partners have agreed that the general juvenile reoffending rate (32 per cent) may be taken as a sensible proxy for the number of individuals who are prosecuted for breaching one, or more, of their YDO conditions. It is worth noting that police may deal with breaches through other means, such as through formal warnings or variations of the YDO, for initial, or less serious, breaches, but this is not reflected in this appraisal as it is assumed to be covered in monitoring costs. As a result, the overall number of prosecutions and convictions for breaching a YDO may be lower in practice.
In the year ending September 2024, 85 out of 86 terrorism related trials resulted in convictions. For the purposes of this appraisal, it is assumed that all individuals who are prosecuted for breaching a YDO, will be convicted.^{[footnote 17]}
The custodial rate for being convicted of breaching a YDO is assumed to be 18 per cent, similar to the custodial rate of breaching other legal measures for individuals aged between 10 to 21, such as youth rehabilitation orders and detention and training orders.
It is assumed that individuals who are convicted of breaching a YDO will receive either a custodial sentence or a community sentence-like outcome but not both.
The average number of individuals aged 10 to 21 being convicted and sentenced to immediate custody each year for terrorism related offences is expected to remain constant in the baseline (without the introduction of YDOs).
The two cohorts that have been considered in this appraisal are individuals who have committed terrorism related offences, and individuals who are involved in terrorism related activity. These cohorts have been considered appropriate proxies for the type of conduct that would be eligible for a YDO. Due to the similarities between the cohorts of individuals in this appraisal and individuals currently in custody for terrorism related offences, it is assumed that a proportion of past convicted individuals could have been diverted from custodial sentences if YDOs were available.
In consultation with operational partners, the assumption has been provided that between 25 and 75 per cent of individuals aged between 10 to 20, who are currently sentenced to immediate custody for terrorism related offences, could have been diverted from custodial sentences with the use of YDOs.
Based on the above assumptions, it is assumed that an annual volume of individuals are diverted from custodial sentences with the implementation of YDOs. The high scenario assumes fewer individuals will be diverted while the low scenario assumes a higher volume of individuals will be diverted.
It is assumed that the individuals who are forecasted to be diverted by YDOs but would have received a custodial sentence otherwise, would have received a custodial sentence of 2.5 years, which is based on the lower estimate of the average custodial sentence for terrorism related offences. The use of a lower estimate is due to a significant volume of those aged under 18, who have been convicted of a terrorism related offence, receiving non-custodial or less severe sentences.
Individuals who are convicted of breaching their YDO, receive a custodial sentence, and are aged under 18 years will receive a maximum custodial sentence of 24 months. They will be eligible for early release. It is assumed that they will serve 12 months in prison and the remaining 12 months on licence.
Individuals who are convicted of breaching a YDO, receive a custodial sentence, and are aged over 18 years, will receive a maximum custodial sentence of 2 years. They will be eligible for early release. It is assumed that they will serve 16 months in custody and the remaining 8 months on licence. This is consistent with MoJ guidelines for adults sentenced to custody.
Individuals who are convicted of breaching a YDO and receive a community sentence outcome will receive a sentence similar to a youth rehabilitation order.
The cost of administrating and monitoring an individual issued a community sentence outcome is assumed to be similar for adults and juveniles.
The approximate cost of a trial in a Magistrate Court for adults and juveniles is the same.
It is estimated that 50 per cent of individuals who breach their YDO will plead guilty, based on historic guilty pleas for terrorism related offences^{[footnote 18]}. The rest are expected to plead not guilty and require longer trials. The time taken for a trial to conclude is based on historic casework.
The cost of monitoring a juvenile and an adult is similar.
All individuals are entitled to legal aid and are assumed to take it.

Measure 1A: Costs

43. Monetised costs have been omitted for operational sensitivity. Instead, the methodology of monetised costs has been presented below.

44. There are familiarisation costs for CTP. The number of CTP officers who need to be familiarised is not known with any degree of certainty. It is assumed that between 25 per cent and 75 per cent (with central estimate of 50 per cent) of CTP officers will be required to familiarise themselves with the relevant legislation. The legislation length for Youth Rehabilitation Orders has been used as a proxy for the legislative length of YDOs.

45. There are ongoing training costs, as CTP officers must be routinely trained how to handle and enforce YDOs. As a proxy, the amount of time required to train CTP officers to handle TPIM subjects has been used to model the cost of YDO training. This time has been multiplied by the labour costs of CTP officers to arrive at the annual training cost per officer. In the first year of implementation, the proportion of CTP officers who require training is taken from the volume of officers who need familiarising.

46. After the initial year, the number of officers who need training is the volume of new officers. This has been calculated by multiplying the volume of CTP officers who need familiarising by the leaving rate of CTP officers. As a proxy, the leaving rate of police officers (4.9 per cent) has been used to model the leaving rate of CTP officers^{[footnote 19]}. Training costs are incurred in every year of the 10-year appraisal period.

47. There will be a cost incurred to the magistrate courts to issue a YDO. The cost of an ‘immediate guilty’ plea magistrate trial has been used as an approximate proxy of the increase in court resource costs. It is assumed that 100 per cent of individuals will be entitled to legal aid which will generate a cost to the Legal Aid Agency (LAA).

48. Similar to other civil and community-based measures, there are monitoring costs associated with those issued YDOs to ensure that subjects are following all required measures. Probation costs have been used as an appropriate proxy for the increase in resource costs.

49. As part of the YDO, individuals will be required to attend deradicalisation focussed sessions similar to Desistance and Disengagement Programme (DDP) and other Home Office-accredited interventions. The costs of DDP interventions have been used as an appropriate proxy for the annual cost of de-radicalisation sessions, although the interventions required in practice may incur lower costs than DDP which is the most intensive type of intervention. The cost of de-radicalisation is the greatest cost incurred.

50. A proportion of individuals are expected to be convicted for breaching their YDO. The volume of individuals who breach their YDOs and are prosecuted will generate a cost to the Crown Prosecution Service (CPS), Magistrates’ Courts and the LAA.

51. As mentioned in the measure specific assumptions, 18 per cent of those who breach their YDOs are expected to be sentenced to immediate custody. They will incur a cost to the CJS through prison and probation costs. Costs for those aged over 18 and under 18 years have been separately calculated to account for the differences in resources required to imprison them.

52. The remaining 82 per cent of individuals who breach their YDO are expected to be given community sentence like outcomes. This will a incur a cost to the CJS through probation like costs.

53. Familiarisation and ongoing training costs for operational partners have not been monetised due to the sensitivity of this information.

54. It has not been possible to monetise the wider societal impact of individuals breaching a YDO as it is unknown how individuals will breach their YDO and to what extent. For instance, by continuing to engage in terrorist activity. However, in the baseline option it is likely that individuals would continue to pursue terrorist activity, so the costs should nullify if the terrorist activities are assumed to be of equal severity and quantity.

Measure 1A: Benefits

55. The methodology of benefits has been presented below. Numbers have been omitted for operational sensitivity.

56. There are savings to the prison system from individuals being potentially diverted by the implementation of YDOs. Overall, the measure is expected to cause a net reduction in the number of individuals sentenced to prison. This is due to two decreasing effects. Firstly, the measure will divert more individuals from prison than it introduces. Secondly, the proposed sentence length for breaching a YDO is shorter than the average sentence length for terrorism related offences, meaning individuals spend less time in prison than otherwise.

57. Combining the effects, the measure is expected to provide a net reduction in the annual number of prison places needed. Consequently, the measure should provide an overall net reduction in the resource requirements of the prison service. This applies to all age demographics.

58. Furthermore, there are cost savings to the Crown Courts and CPS as there may be cases where, rather than being taken forward to prosecution, the CPS consider it appropriate for the police to apply for a YDO where terrorism related offences have been committed, avoiding the need for a criminal trial.

59. It is important to recognise that the YDO would not prevent the CPS from taking forward a prosecution if the relevant prosecutorial tests were met. The cost of prosecuting and convicting an adult has been used as an appropriate proxy. Alongside court costs, there are also savings for the LAA as they no longer need to provide legal aid to these individuals.

60. Operational savings to operational partners have not been monetised due to the sensitivity of the information regarding resource usage per individual. It is believed that there are significant operational savings to operational partners from the implementation of YDOs.

61. There are potentially additional non-monetised security benefits as individuals are diverted from committing additional terrorism related offences that inflict harm on society. The physical threat to people from terrorist activity can result in deaths or serious injury. The objective of the YDO is to provide a tool for operational partners that will divert individuals earlier from terrorist activities and could produce a much lower risk outcome than Option 0. Reduced risk would be beneficial to UK citizens’ wellbeing. Although, it should be noted that the risk that these young individuals pose and the effect of the measure in reducing the risk cannot be explicitly quantified.

Measure 1A: NSPV

Table 1: NPSV of measure 1A (£ millions, 2026/27 prices)

	Low	Central	High
NPSV	-0.69	-12.83	-29.68

The granular breakdown of costs and benefits have been omitted due to operational sensitivity

Source: Home Office internal estimates, 2026

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

Measure 1B: Assumptions

62. This measure is expected to be implemented in July 2026; costs and benefits are assumed to be incurred for remaining nine months of the financial year 2026/27. Ongoing costs and benefits occurring in the first year are therefore 75 per cent of subsequent years. Transition costs and benefits are incurred in full.

63. The following assumptions have been used for the analysis of this measure:

The volume of new or revived TPIM issuances is expected to remain constant over the 10-year appraisal period at 3.5 per year.
The TPIM breach rate for other measures is expected to remain constant at 38 per cent of issued TPIMs. This equates to 1.25 TPIM breaches per year.
In the year ending September 2024, 85 out of 86 terrorism related trials resulted in convictions. For the purposes of this appraisal, it is assumed that all individuals who are prosecuted for breaching a TPIM, will be convicted.^{[footnote 20]}
There are currently no TPIM subjects, so these have been omitted from this analysis, as there is no indication that this is likely to change.
Based on the historic custodial rate for prosecuted and convicted TPIM breaches, 87 per cent of breaches of this measure would result in a custodial sentence.
Based on the average custodial sentence for individuals who breach a TPIM measure, an individual who breaches the TPIM measure and receives a custodial sentence will be sentenced to 22.5 months in prison where it is assumed that they will serve two-thirds of the sentence, before being released on licence to serve the remaining third in the community
Based on the length of previous community sentences for TPIM breaches, the average community sentence for an individual who breaches the measure and receives a community sentence would be 7.7 months.
All individuals are entitled to legal aid and are assumed to take it.

Measure 1B: Costs

64. There are assumed to be no training costs for this measure, as CTP officers are already trained in handling and enforcing TPIM measures similar to the proposed amendment. Consequently, officers will not require any upskilling. The measure will not incur additional monitoring costs as CTP officers have been previously monitoring TPIM subjects for similar weapon measures. As a result, the measure will not generate additional monitoring burden, and no resourcing costs.

65. There are familiarisation costs for CTP officers. It is assumed that the length of the document that will be used to familiarise officers will be between 70 words to 500 words (based off the length of previous TPIM measures). As it is difficult to estimate the actual volume of officers that will need familiarising, a broad approach has been taken. it is assumed that the document will need to be read by:

50 per cent to 100 per cent of constables (with central estimate of 75 per cent)
25 per cent to 100 per cent of sergeants (with central estimate of 50 per cent)
5 per cent to 15 per cent of senior officers (with central estimate of 10 per cent)

64. The cost of familiarisation for CTP officers over the 10-year appraisal period is estimated to be between £0 and £2,500, with a central estimate of £600 (2026/27 prices).

65. A central estimate of 25 per cent is used. The low estimate of 0 per cent reflects the possibility of no additional breaches, while the high estimate is set at 100 per cent to account for all unlikely but possible scenarios. This wide range is intended to capture uncertainty and ensure all realistic and extreme scenarios are included. This would result in an increase of 0 to 12.5 TPIM breaches over the 10-year appraisal period, with a central estimate of 3.1 TPIM breaches. These breaches would be split between individuals who receive custodial sentences and individuals who receive community sentences. Legal aid and CPS costs are estimated to cost between £0 and £121,800 over the 10-year appraisal period with a central estimate of £30,500 (2026/27 prices).

66. As mentioned in the measure specific assumptions, an 87 per cent custodial rate would result in between 0 and 10.8 individuals who breach the measure being sentenced to immediate custody over the 10-year appraisal period with a central estimate of 2.7 individuals over the 10-year appraisal period. The 10-year discounted cost of prison and probation costs for individuals who breach the measure is expected to be between £0 and £674,900 over the 10-year appraisal period with a central estimate of £168,700 (2026/27 prices).

67. The remaining 13 per cent of individuals who breach the new TPIM measure are expected to receive community sentences. The breaches would result in between 0 and 1.7 individuals being sentenced to community sentences over the 10-year appraisal period with a central estimate of 0.4 individuals. This would incur a discounted cost to the justice system between £0 and £3,900 over the 10-year period with a central estimate of £700 (2026/27 prices)

68. The historic TPIM appeal rate is extremely low, and no subject has appealed a measure similar to the one presented. As a result, it is not believed that the inclusion of this measure will create additional appeals. Appeals have not been included in monetised costs.

69. The 10-year total discounted costs for this measure ranges between £0 million and £0.80 million, with a central estimate of £0.20 million (2026/27 prices).

Measure 1B: Benefits

70. There are no monetised benefits to this measure.

71. This measure is expected to produce non-monetised benefits including additional security benefits from the reduction in risk that TPIM subjects pose to the UK. Although currently unquantifiable, TPIM subjects may pose a substantive risk to the UK, as for a TPIM to be imposed, there must be reasonable belief that the individual has been involved in terrorism related activity.

72. The measure is expected to provide greater risk management of TPIM subjects by providing the legal means to limit the access of the subjects to offensive weapons that could harm British citizens or property. As a result, the potential risk that TPIM subjects pose to UK citizens may be reduced by this measure. It should be noted that it is not currently possible to quantify the risk reduction that the measure may provide.

Measure 1B: NPSV

Table 2: Total present value costs, benefits, and NPSV of measure 1B (£ millions, 2026/27 prices)

	Low	Central	High
Legal Costs	0.00	0.03	0.12
Prison costs	0.00	0.17	0.67
Probation costs	0.00	0.01	0.03
Familiarisation costs	0.00	0.00	0.00
Total costs	0.00	0.20	0.80
Total benefits	0.00	0.00	0.00
NPSV	0.00	-0.20	-0.80

Source: Home Office internal estimates, 2026; numbers may not sum due to rounding

73. The net present social value of this measure ranges between £ 0 million and -£0.80 million, with a central estimate of -£0.20 million (2026/27 prices)

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

74. This measure is expected to be implemented in July 2026; costs are assumed to be incurred for remaining nine months of the financial year 2026/27. Ongoing costs occurring in the first year are therefore 75 per cent of subsequent years. Transition costs are incurred in full.

75. The initial assessment, based on engagement with PSNI and CTP, is that the new seizure power will most likely be used in Northern Ireland, and the appraisal focuses on the impact within Northern Ireland. CTP have been consulted and they do not expect this measure to be regularly used in Great Britain.

Measure 1C: Costs

76. As the seizure of articles will not be used in criminal proceedings, there will be no additional costs to the CJS from individuals being prosecuted.

77. All Northern Irish police officers will be familiar with section 13 of TACT 2000. The changes to legislation are relatively minimal with less than 40 words being added to the existing legislation. Consequently, the Home Office has assumed that the time taken to familiarise officers will be less than one minute. As a result, the marginal familiarisation costs will be zero.

78. A similar logic applies to training costs as PSNI officers will not require any upskilling to use section 13 powers. The measure is also likely to introduce a new destruction power for relevant articles seized. However, this is unlikely to result in additional training costs to PSNI officers given that they will be familiar with destroying harmful articles in other contexts.

79. The volume of additional seizures made under section 13 is expected to be minimal. Furthermore, in line with the previous Counter Terrorism and Border Security Bill Impact Assessment^{[footnote 21]}, the time taken to remove and destroy the article is assumed to be zero. As a result, it is assumed that the measure will not provide any additional burden to officers.

80. This results in a total net present cost of £0.00 million (2026/27 prices).

Measure 1C: Benefits

81. There are currently no monetised benefits to this measure. A potential non-monetised benefit of the measure is the increase in the police’s flexibility to respond to the actions of proscribed organisations, as well as the decreased visibility of articles relating to proscribed organisations which could potentially lead to lower levels of support. As a consequence, the public’s confidence in the police’s ability to respond to the actions of proscribed organisations could increase, leading to reduced community tensions.

Measure 1C: NPSV

82. The net present social value of this measure is £0.00 million over the 10-year appraisal period.

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.

Measure 1D: Approach to appraisal

83. This measure is expected to be implemented in July 2026; costs are assumed to be incurred for remaining nine months of the financial year 2026/27. Ongoing costs occurring in the first year are therefore 75 per cent of subsequent years. Transition costs are incurred in full.

84. The Home Office has been unable to monetise the total costs generated by the measure due to the uncertain volume of potential offences and offenders expected under an extended section 13(1) of TACT 2000.

85. There is currently no centrally recorded data of instances of prison staff detecting section 13 articles within a prison setting, making it difficult to estimate the volume of offences/offenders. Furthermore, the IRTL noted in his Terrorism in Prisons report^{[footnote 22]} that due to the nature of the offence in a prison setting, it is often difficult to attribute the offence to a specific individual (for example, the possession of proscribed organisations’ flags in shared cells).

86. As a result, even if it was feasible to estimate the prevalence of the offence, it would be difficult to estimate the volume of connected offenders. In addition, the Home Office have not been able to identify any suitable proxies that could reliably indicate the potential volume of offences/offenders that will be prosecuted. Consequently, in the absence of volumes, the department cannot reliably monetise the measure’s impact on the police, legal system and prisons.

87. However, an estimate of the monetised cost per offender is presented below, as suitable estimates of the unit costs associated with an extended section 13(1) of TACT 2000 are available.

Measure 1D: Assumptions

88. The following assumptions have been used for the analysis of this measure:

As part of the Crime in Prison Referral Agreement^{[footnote 23]}, if a crime is classed as a terrorism or terrorism-connected offence, it is mandatory for prisons to refer an offence committed by a prisoner to CTP to investigate and seek prosecution. As this provision will be a terrorism offence, it is assumed that 100 per cent of offenders will be referred to CTP and investigated.
The proportion of offenders that CTP decide to prosecute is unknown as the decision to prosecute is based on operational considerations. If offenders are not prosecuted, they would be processed through the prisons’ adjudication (prison discipline) system. There is no available proxy for the proportion of offenders as there are no readily available statistics regarding the number of prison referrals that result in prosecution.
As the cost of prosecution is significantly greater than the cost of the internal adjudication system and the proportion of offenders that CTP decide to prosecute is unknown, this appraisal takes a conservative approach^{[footnote 24]}. It assumes that all individuals will be prosecuted. Only the costs of prosecuting offenders are presented here but it should be noted that not all processed offenders will be prosecuted.
If convicted of an offence under an extended section 13(1) of TACT 2000, a proportion of offenders will be given an additional custodial sentence to serve consecutively to their original sentence^{[footnote 25]}. The exact proportion of offenders given additional custodial sentences is unknown and will be dependent on a variety of aggravating factors.
For context, the historic custodial rate for an unauthorised possession of a mobile phone within prison offence for adults is 86 per cent while the historic custodial rate for possession of an offensive weapon in prison for adults is 91 per cent^{[footnote 26]}. As a result, it is assumed that the vast majority of those convicted will be given custodial sentences between the above rates (86 to 91 per cent). The remaining 9 to 14 per cent will be given fines^{[footnote 27]}.
If prosecuted and convicted for breaching this offence and given a custodial sentence, the individual would receive a custodial sentence of up to six months. This is the maximum sentence for this offence. It is difficult to specify what the average sentence will be. As a result, this appraisal has adopted a conservative approach^{[footnote 28]}.
This appraisal assumes that all custodial sentence lengths for the breaches of an extended section 13(1) of TACT 2000 will be six months. As the additional sentence will be served consecutively to their original offence, it is assumed that all convicted individuals who are given custodial sentences, will serve an additional six months in prison.
In the year ending September 2024, 85 out of 86 trials for terrorism related offences resulted in convictions. For the purposes of this appraisal, it is assumed that all individuals who are prosecuted for breaching this measure, will be convicted.^{[footnote 29]}

Measure 1D: Costs

89. Prison officers will need to become familiar with any relevant guidance. It is assumed that the word length of a document used to familiarise officers with section 13(1) of TACT 2000 will be between 900 and 1,000 words. This is based on:

the word length of a section of the current guidance relating to the control of prohibited items in prisons and^{[footnote 30]}
the word length of section 13 of the TACT 2000 legislation^{[footnote 31]}.

90. An estimated range of between 25 and 75 per cent of prison officers are required to be familiar with the new legislation, with a central estimate of 50 per cent. In line with the method outlined in paragraph 36, the total cost of familiarising prison officers is estimated to be between £3,000 and £57,700, with a central estimate of £20,700 (2026/27 prices). There will be no familiarisation costs for CTP officers as they will be familiar with the application of section 13 in a public setting.

91. There will be no training costs as prison officers are trained in the procedures regarding searching and seizing similar prohibited items. CTP officers are trained in prison referrals and investigation of section 13(1), TACT 2000 offences.

92. It is assumed that the measure would not increase the resource burden on HM Prison and Probation Service (HMPPS) having to conduct additional searches. Prison officers will already be conducting cell searches as part of their routine operations, and it is assumed that the number of additional searches carried out will be zero.

93. However, the introduction of the measure would increase the resource burden on HMPPS if prohibited items are found as prison officers would have to process the offender and any accompanying evidence. Consequently, the measure generates a labour cost to HMPPS – which is in the firm of the opportunity cost associated with the time required for relevant form filling - by increasing the workload of prison officers. Based on:

the number of forms that need to be filled out as part of an adjudication process,
the average speed of an individual completing the form and
the average hourly labour cost of a prison officer.

94. The additional labour cost associated with processing the offender and any accompanying evidence is estimated to be between £27 and £36 per offender (2026/27 prices).

95. Additional costs will be incurred by CTP if an offence under an extended section 13(1) of TACT 2000 is referred. The exact costing for this referral is unknown. The estimate used here is based on police investigation costs of other comparable crimes^{[footnote 32]}. The cost of a referral to CTP is estimated to be between £300 and £7,700, with a central estimate of £1,400 (2026/27 prices)

96. Regardless of whether the prison refers an offender to the police or not, the offence will generate a cost to the prison if the prison decides to place the prisoner on report and an adjudication hearing takes place^{[footnote 33]}. Based on data from MoJ, the cost of a single adjudication hearing is estimated to be between £100 and £180 per offender, with a central estimate of £130, depending on the region and complexity of the offence (2026/27 prices)

97. Costs will be incurred by the legal system as offenders will be prosecuted and sentenced for committing offences under an extended section 13(1) of TACT 2000. The average cost per offender is estimated to be £7,500 and £7,800, with a central estimate of £7,700, which is incurred by the LAA, CPS and HM Courts and Tribunals Service. There will be additional costs to HMPPS in enabling prisoners to attend proceedings. The cost of transporting a prisoner is estimated to be between £1,400 and £1,800, with a central estimate of £1,600 (2026/27 prices). Transport costs include labour plus other miscellaneous expenses.^{[footnote 34]}

98. As it assumed for the purpose of this analysis, offenders who are convicted and sentenced to custodial sentences will serve an additional six months in prison, the measure will generate a cost to HMPPS to imprison the individual. See paragraph 36.

99. Overall, the monetised cost per offender who is prosecuted and convicted is between £0.01 million and £0.05 million with a central estimate of £0.04 million^{[footnote 35]}.

Measure 1D: Benefits

100. A non-monetisable benefit of the measure is the potential improved management of terrorist risk posed by offenders within and outside of prisons.

101. The 2019 terror attack in HMP Whitemoor and the subsequent 2022 Terrorism in Prisons report by the IRTL^{[footnote 36]}, highlighted the risk of terrorist violence within prisons. By enabling prisons to exercise greater control over prisoners’ ability to display the potentially radicalising material associated with proscribed organisations in prisons, the measure could reduce a proscribed organisation’s influence within and outside of prisons. The Terrorism in Prisons report suggests that several past terrorism offences have been linked to associations or ideologies formed in prison.

102. Reducing the influence of proscribed organisations may reduce the risk that these organisations pose to UK citizens’ safety and wellbeing, particularly when affiliated offenders are released from prisons. Several of the last successful terrorist attacks in the UK were carried out by current/former prisoners. As a result, reducing the risk of radicalisation within prisons may reduce the risk that prisoners pose to the public when released.

103. The IRTL highlighted that the public’s confidence in the CJS is shaken if terrorism is allowed to occur in prisons. If this legislation allows prisons to have a better control of proscribed organisations within prison settings, improved confidence in the CJS which may translate to the reduced fear of terrorism among the general public.

104. However, the analysis presented here has been unable to quantify nor monetise the measure’s benefits.

Measure 1D: NPSV

Table 3: Total costs per prosecuted offender of measure 1D (£ millions, 2026/27 prices)

	Low	Central	High
Monitoring costs	0.00	0.00	0.00
Court costs	0.01	0.01	0.01
CTP referral costs	0.00	0.00	0.01
Additional custodial sentence costs	0.00^{[footnote 37]}	0.03	0.03
Total costs	0.01	0.04	0.05
Total benefits	0.00	0.00	0.00
NPSV per offender	-0.01	-0.04	-0.05

Source: Home Office internal estimates, 2026

Measure 1E: Management of historic terrorist-connected offenders

105. This measure is expected to be implemented in July 2026; costs are assumed to be incurred for remaining nine months of the financial year 2026/27. Ongoing costs occurring in the first year are therefore 75 per cent of subsequent years. Transition costs are incurred in full.

Measure 1E: Costs

106. Based on discussions with CTP, the maximum number of offenders that this measure could apply to over the 10-year appraisal period is 40. However, CTP have highlighted:

that not all offenders will have this measure applied; and
the rate that which it will be applied is highly uncertain. The analysis presented here employs a low (one offender), central (fifteen offenders) and high (forty offenders) range.

107. The timing of when the measure could be applied by CTP during the 10-year appraisal period is uncertain. As a result, the number of offenders which this tool is applied to per year is expected to be between 0.1 and 4.0 offenders, with a central estimate of 1.5.

108. As referenced in paragraph 34, the police or the Secretary of State will be able to apply to the courts to impose the terrorist notification. This will incur a cost to fulfil the additional court documents required. The cost of producing a legal document has been calculated by multiplying the labour hours required to complete by the wage of the officer that completes the documents.

109. For the low estimate, the wage rate of a constable has been used while the high estimate uses the wage rate of a sergeant. Overall, the completion of the legal documents is expected to take between 8 and 16 hours. Overall, the discounted cost of producing legal documents over the 10-year appraisal period is expected to be between £1,400 and £92,600, with a central estimate of £27,300 (2026/27 prices).

110. The measure will incur legal costs as the courts must be satisfied beyond “reasonable doubt” that the offender’s offence had a necessary connection to terrorism. This generates legal costs to CTP including the initial legal costs and cost of appointing counsel, the use of closed material procedure (CMP)^{[footnote 38]}, the cost of defending a judicial review and time cost of CTP attendees. The 10-year discounted legal cost to CTP is expected to be between £12,900 and £3,441,400, with a central estimate of £419,400 (2026/27 prices).

111. Additionally, prison transport costs are incurred by HMPPS to enable prisoners to attend the hearings to determine whether the notification requirement should be applied, although released offenders will not require transport. The 10-year discounted cost of transporting prisoners is expected to be between £0 and £61,100, with a central estimate of £18,300 (2026/27 prices). The costs incurred to HMPPS include staff pay and other costs associated with the transport of prisoners.

112. Lastly, the measure is expected to increase the cost of a prisoner release. The cost is incurred as officers are required to complete a part 4 notification as part of the offender’s release, which incurs a labour cost (see paragraph 34). This produces a discounted cost over the 10-year appraisal period of between £200 and £7,900 with a central estimate of £3,000 (2026/27 prices).

113. This results in a total net present cost of between £0.01 million and £3.60 million, with a central estimate of £0.47 million (2026/27 prices).

Measure 1E: Benefits

114. There are no monetisable benefits to this measure.

115. The measure should provide non-monetised security benefits by helping the police and probation service manage the risk posed by the specific cohort of historic terrorist-connected offenders upon release from custody. Although, the Home Office have been unable to quantify the potential decrease in risk posed by historic terrorist connected offenders.

Measure 1E: NPSV

Table 4: Total costs, benefits, and NPSV of measure 1E (£ millions, 2026/27 prices)

	Low	Central	High
Increased cost of prison releases	0.00	0.00	0.01
Cost of producing court documents	0.00	0.03	0.10
Legal costs to CTP	0.01	0.43	3.53
Prisoner attendance costs	0.00	0.02	0.06
Total costs	0.01	0.47	3.60
Total benefits	0.00	0.00	0.00
NPSV	-0.01	-0.47	-3.60

Source: Home Office internal estimates, 2026

116. The NPSV value of this measure ranges between -£0.01 million and -£3.60 million, with a central estimate of -£0.47 million (2026/27 prices).

BNPV and EANDCB – all measures

117. The monetised costs across all measures have no impact on business, so both the Business Net Present Value (BNPV) and the equivalent annual net direct cost to business (EANDCB) are zero for all measures.

E. Wider impacts

Equalities

118. An Equalities Impact Assessment across measures has been carried out in addition to this EN. Please see this for further detail^{[footnote 39]}.

Better Regulation

119. These proposals are not considered to be regulatory provisions and are out of scope of the Small Business Enterprise and Employment Act 2015. As these measures do not affect businesses of any size, no Small and Micro Businesses Assessment (SaMBA) is required.

Environmental Impact Assessment

120. The Home Office expect there to be no environmental impacts as a result of the options within this EN. The policies meet the environmental principles in accordance with the Environment Act 2021.

International Trade

121. There are no international trade implications from the options considered in this EN.

F. Sensitivity

122. As the equivalent annual net direct costs to the public sector are less than +/- £20 million, an Impact Assessment is not required for this intervention, and an Economic Note has been prepared instead.

123. Overall, ranges have been used to account for most of the uncertainty surrounding figures with anticipated costs and benefits being relatively small. However, to account for where assumptions may lack certainty, sensitivity analysis has been conducted and presented below.

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

124. Currently, it is assumed that the custody rate of breaching the proposed TPIM measure is 87 per cent which is based on the custody rate of TPIM breaches. Sensitivity analysis has been conducted to consider the impact on costs if 100 per cent of convicted individuals are sentenced to immediate custody. This may occur if, for instance, judges believe that convicted individuals pose a severe risk to the public.

125. The total discounted costs would increase between £0 and £97,000 over the 10-year appraisal period, with a central estimate of £25,500 (2026/27 prices).

Table 5: Sensitivity analysis considering the impact on Measure 1B costs of a 100 per cent custody rate (£ millions, 2026/27 prices)

Scenario	Custody Rate: 87 per cent	Custody Rate: 100 per cent
Low	0.00	0.00
Central	0.20	0.23
High	0.80	0.90

Source: Home Office internal estimates, 2026

G. Risks

126. General analytical risks, as well as measure-specific analytical risks, are presented below with brief descriptions of how the risk was mitigated.

Measure 1A: Youth Diversion Orders.

The net effect on prison places – volume of individuals being issued YDOs

127. The actual volume of individuals issued YDOs could significantly differ from expected volumes. With an increased number of individuals being issued YDOs, there could be a potential increase in the number of individuals who breach their YDO and are imprisoned as a result. However, by following existing youth justice frameworks, practitioners are unlikely to seek to prosecute for an offence in respect of most breaches, instead favouring informal resolutions before seeking variations to the order or considering the imposition of other community sentences. There is a risk that the measure imprisons more individuals than it diverts, however even in the most extreme scenarios the YDO measure is expected to divert more individuals from prison than it introduces.

128. The actual number of YDOs issued must exceed the proposed number by a significant amount before the measure is expected to have a net positive effect on expected prison places. The ranges cover any extreme but possible scenarios where the number of YDOs increase significantly.

The net effect on prison places - volume of individuals being diverted by YDOs

129. YDOs could divert fewer individuals than estimated. There is a risk that individuals are not diverted as the offences that they commit are too severe or the use of a YDO would be inappropriate. As a result, those individuals may end up with a criminal conviction and sentenced to prison. Consequently, the measure may divert fewer individuals from prison then it sends.

130. Similar to above, a large range of possible volumes of individuals diverted has been used. It is estimated that, even in the most extreme scenarios, YDOs are expected to divert more individuals from prison than it introduces.

The net effect on prison places – the breach rate

131. A risk is that the number of individuals who breach a YDO is much higher or lower than expected. This may generate a cost to the legal, prison and probation services. The Home Office have modelled several different scenarios with differing number of individuals who breach their YDO to account for this.

The net effect on prison places – age demographics of breaches

132. A risk is that the age demographics of individuals who receive a YDO and the age demographics of individuals who breach a YDO are not similar to the current age demographics of individuals who are convicted of terrorism related offences. As a result, there could be net increases in prison places for certain age demographics. However, there is no evidence to suggest that the age demographics are different, and there would have to be a significant divergence for a noticeable change to occur.

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

Number of TPIM/STPIMs issued

133. The main analytical risk is that the actual volume of new TPIMs/STPIMs issued per year differs significantly from expected. This would increase/decrease the estimated number of potential TPIM breaches and costs. There is no indication that this is the case as the average number of TPIMs issued per year remains relatively stable. However, the figures provided are indicative based on previous years and may not be representative of actual volumes over the 10-year appraisal period.

The number of appeals

134. There is a risk that individuals appeal this measure which would incur a cost to the legal system. There is no precedent of TPIM subjects appealing this type of measure. As a result, it is assumed that there will be no appeals.

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

135. As there are no estimated monetised costs or benefits, the analytical risk is minimal. Engagement with PSNI and CTP indicates that any additional seizures will be small in volume and absorbed within existing operational activity.

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

136. Historic appeal rates for comparable terrorism‑related measures are extremely low, with no recorded appeals for similar TPIM‑related provisions. Because these offences are usually supported by strong, well‑documented evidence within the prison environment, the likelihood of a successful appeal is low. It is assumed for the purposes of this analysis that no individual will appeal this offence; appeal costs have therefore not been monetised.

Measure 1E: Management of historic terrorist-connected offenders

137. There is uncertainty regarding the number of offenders that this measure may apply to. CTP estimate that the maximum number of offenders that this measure may impact is forty but highlighted that it is unlikely that all offenders will have this measure applied.

138. As total costs scale directly with offender volume, there is a risk that the analysis over- or under-estimates costs if the number of offenders that this measure applies to differs from the assumptions used.

H. Annex

Mandatory specific impact test - Statutory Equalities Duties

The Home Office assesses that these measures will not directly discriminate within the meaning of the Equality Act 2010, with the exception of the YDO which will directly discriminate on the basis of age. The YDO will only be available to those aged under 21 years at the time that the police make the application to the courts. Most of the proposed changes may result in some indirect discrimination on certain protected characteristics. For example, the UK’s definition of terrorism, which terrorism offences are based on, includes the use or threat of action where this is made for the purpose of advancing a cause, including a religious cause. As a result, the statistics on terrorist offenders may over-represent certain religions in comparison to the make-up of religious beliefs across the UK.

The department assesses that any indirect discrimination would be objectively justified as a proportionate means of achieving the government’s legitimate aim of protecting the public from the threat of terrorism.

The SRO has agreed these findings.

Complete: Yes

Chapter 8.40, The Terrorism Acts in 2022 ↩
Chapter 9 Recommendations, The Terrorism Acts in 2022 ↩
Recommendation 2, Terrorism in Prisons: https://terrorismlegislationreviewer.independent.gov.uk/wp-content/uploads/2022/04/Terrorism-in-Prisons.pdf ↩
BBC: https://www.bbc.co.uk/news/uk-england-cambridgeshire-54449183 ↩
BBC: https://www.bbc.co.uk/news/uk-england-london-57260509 ↩
BBC: https://www.bbc.co.uk/news/live/uk-51350195 ↩
GOV.UK: https://www.gov.uk/government/publications/counter-terrorism-strategy-contest-2023 ↩
GOV.UK: https://www.mi5.gov.uk/director-general-ken-mccallum-gives-latest-threat-update ↩
Chapter 7.88, The Terrorism Acts in 2021: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1140911/E02876111_Terrorism_Acts_in_2021_Accessible.pdf ↩
Chapter 8.40, The Terrorism Acts in 2022 ↩
Section 33, National Security Act 2023: https://www.legislation.gov.uk/ukpga/2023/32/section/33 ↩
Recommendation 2, Terrorism in Prisons: https://terrorismlegislationreviewer.independent.gov.uk/wp-content/uploads/2022/04/Terrorism-in-Prisons.pdf ↩
Accommodation mostly used for people on licence, but they also accommodate small numbers of people on bail or community sentences. They have supervision for those deemed ‘high risk’. ↩
The speed at which individuals are assumed to read the guidance is taken from: https://readingsoft.com/ ↩
ONS Index of Labour Costs per Hour (2020): https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/earningsandworkinghours/datasets/indexoflabourcostsperhourilchseasonallyadjusted ↩
Only familiarisation costs are displayed here. It has not been possible to monetise the total costs generated by the measure due to the uncertain volume of potential offences and offenders expected, see paragraphs 84 to 86. A cost per offender is estimated but not displayed here; see paragraphs 93 to 98. ↩
GOV.UK: https://www.gov.uk/government/statistics/operation-of-police-powers-under-tact-2000-to-september-2024 ↩
GOV.UK: https://www.gov.uk/government/statistics/operation-of-police-powers-under-tact-2000-to-september-2024 ↩
Institute for Government: https://www.instituteforgovernment.org.uk/sites/default/files/2023-10/Retention-in-public-services.pdf ↩
GOV.UK: https://www.gov.uk/government/statistics/operation-of-police-powers-under-tact-2000-to-september-2024 ↩
https://assets.publishing.service.gov.uk/media/5b9bd9ffed915d6efa0000b4/CTBS_Bill_Impact_Assessment_Lords_Introduction.pdf ↩
https://assets.publishing.service.gov.uk/media/6267f916d3bf7f55c910e84e/terrorism-in-prisons.pdf ↩
https://www.gov.uk/government/publications/handling-crimes-in-prison-protocol/crime-in-prison-referral-agreement ↩
In that costs are likely overestimated. ↩
Based on totality sentencing guidelines, an additional custodial sentence will be served consecutively to the original sentence. ↩
Custody rate includes all prisoners. The rate is not specific to terrorism related offenders. ↩
In policy appraisal more generally, if an individual is convicted and given a fine, there is no economic cost as it is simply an economic transfer. ↩
In that costs are likely overestimated. ↩
https://www.gov.uk/government/statistics/operation-of-police-powers-under-tact-2000-to-september-2024 ↩
Managing conveyance of unauthorised and illicit items policy frameworks (open and closed prisons) - GOV.UK: https://www.gov.uk/government/publications/managing-conveyance-of-unauthorised-and-illicit-items-policy-frameworks-open-and-closed-prisons ↩
Section 13, Terrorism Act 2000: https://www.legislation.gov.uk/ukpga/2000/11/section/13 ↩
Comparable crimes include possession of drugs, possession of offensive weapons and miscellaneous crimes against society. ↩
Any adjudication would be adjourned whilst the police are investigating to avoid double jeopardy ↩
This is based on the transport costs for similar offences. ↩
The lower bound being set at £0.02 million is based on the stated assumption that not all convicted offenders will be given additional custodial sentences. Instead, these convicted offenders will be given fines. However, as most convicted offenders will be given additional custodial sentences, the central estimate assumes that the offender will be given a custodial sentence. The central estimate of cost includes the additional costs of custodial sentences. ↩
https://assets.publishing.service.gov.uk/media/6267f916d3bf7f55c910e84e/terrorism-in-prisons.pdf ↩
As stated above, in the low scenario, it is assumed that the offender does not receive an additional custodial sentence. ↩
A CMP allows courts to protect sensitive material in civil proceedings when national security or other public interests are at stake. ↩
Equality Impact Assessment – Counter-Terrorism and National Security Measures – Home Office (2025) ↩

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Summary Table: Measures included in “Counter Terrorism”.

Youth Diversion Order

Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

Application of certain terrorism offences (wearing of uniform /displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

Management of historic terrorist-connected offenders

Rationale for intervention, objectives and intended effects.

Policy options (including alternatives to regulation)

Costs and benefit summary

Risks

Evidence Base

A. Policy objectives and intended effects

Measure 1A: Youth diversion order

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

Measure 1E: Management of historic terrorist-connected offenders

B. Policy options considered, including alternatives to regulation

C. Past evaluations and rationale for government intervention

Measure 1A: Youth diversion orders.

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence.

Measure 1E: Management of historic terrorist connected offenders.

D. Appraisal

Option 1

Summary table: per-measure central values (£m) rounded to two decimal places (2026/27 prices)

Measure 1A: Youth Diversion Orders

Measure 1A: Assumptions

Measure 1A: Costs

Measure 1A: Benefits

Measure 1A: NSPV

Table 1: NPSV of measure 1A (£ millions, 2026/27 prices)

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

Measure 1B: Assumptions

Measure 1B: Costs

Measure 1B: Benefits

Measure 1B: NPSV

Table 2: Total present value costs, benefits, and NPSV of measure 1B (£ millions, 2026/27 prices)

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

Measure 1C: Costs

Measure 1C: Benefits

Measure 1C: NPSV

Measure 1D: Approach to appraisal

Measure 1D: Assumptions

Measure 1D: Costs

Measure 1D: Benefits

Measure 1D: NPSV

Table 3: Total costs per prosecuted offender of measure 1D (£ millions, 2026/27 prices)

Measure 1E: Management of historic terrorist-connected offenders

Measure 1E: Costs

Measure 1E: Benefits

Measure 1E: NPSV

Table 4: Total costs, benefits, and NPSV of measure 1E (£ millions, 2026/27 prices)

BNPV and EANDCB – all measures

E. Wider impacts

Equalities

Better Regulation

Environmental Impact Assessment

International Trade

F. Sensitivity

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon

Table 5: Sensitivity analysis considering the impact on Measure 1B costs of a 100 per cent custody rate (£ millions, 2026/27 prices)

G. Risks

Measure 1A: Youth Diversion Orders.

The net effect on prison places – volume of individuals being issued YDOs

The net effect on prison places - volume of individuals being diverted by YDOs

The net effect on prison places – the breach rate

The net effect on prison places – age demographics of breaches

Measure 1B: Terrorism and State Threat Prevention and Investigation Measures: unapproved articles capable of being used as a weapon.

Number of TPIM/STPIMs issued

The number of appeals

Measure 1C: Seizure of any article displayed in a public place if it arouses reasonable suspicion that an individual is a supporter or member of a proscribed group.

Measure 1D: Application of certain terrorism offences (wearing of uniform / displaying an article) to conduct in prisons as well as other prescribed places of detention or residence

Measure 1E: Management of historic terrorist-connected offenders

H. Annex

Mandatory specific impact test - Statutory Equalities Duties

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