© National Audit Office 2026

The costs of tackling drug harms in prisons

Ministry of Justice and Department of Health & Social Care

Session 2024–2026
04 February 2026
HC 1643

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Gareth Davies
Comptroller and Auditor General
National Audit Office

27 January 2026

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The National Audit Office study team consisted of:

Liam Blanc, Emma Green, Oliver Jeffries, David Raraty and Joe Warwick, under the direction of Jenny George.

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Key facts

Summary

1 In April 2025, approximately 40,000 people in prisons in England and Wales (50%) had an identified drug problem. Misuse of illicit drugs by people in prison creates or exacerbates risks to their health, well-being and personal safety. Between December 2022 and December 2024, the Prisons and Probation Ombudsman investigated 833 deaths, of which 136 (16%) were drug-related. Conveyance, supply and use of illicit drugs also increase risks to the safety and stability of the prison regime. Availability of drugs inside prisons creates an illicit economy that can fuel debt, which can lead to assault, extortion or self-harm. Prisoners who are using illicit drugs often reoffend after leaving prison.

2 Effective interventions require HM Prison and Probation Service (HMPPS) and health service providers, commissioned for prisons in England by NHS England (NHSE), to work closely together.

HMPPS is primarily responsible for action to detect illicit drugs and prevent their conveyance into prisons, and it also seeks to reduce demand for drugs through initiatives to encourage positive behaviour changes.

Health service providers deliver drug treatment and recovery services inside prisons.

The overall prison environment can support prisoners by providing a rehabilitative culture; education and other purposeful activities; building relationships; delivering a safe regime; and facilitating access to health interventions, including addressing mental health needs.

Focus of our report

3 This report focuses on how the prison and health services are using public funds to tackle drug harms in prisons. It examines:

how well the Ministry of Justice (MoJ), HMPPS, Department of Health & Social Care (DHSC), NHSE and wider government understand the scale and nature of drug harms in prisons (Part One);

the funding available for HMPPS and NHSE to tackle drug harms in prisons, and how resources are prioritised (Part Two); and

how effectively resources have been used and how well the prison and health services work together (Part Three).

4 The report focuses only on illicit drug harms in prisons. We do not cover national and international work by the police and others to counter criminal activity supplying drugs to prisons, nor do we review interventions for people on community orders or the continuity of drug treatment services for prison leavers. ‘Substance misuse’ is a broader term often used in healthcare, which includes misuse of alcohol and diversion of prescription medicines, as well as illicit drugs. We touch on these broader issues where relevant, but they are not the focus of our report. While HMPPS is responsible for prisons in England and Wales, healthcare in Wales is a devolved function provided by NHS Wales, and therefore falls outside the scope of this report.

Key findings

Understanding the nature and extent of illicit drugs in prisons

5 The prison and health services know that they face substantial, increasing and rapidly changing threats from illicit drugs in prisons. In 2024-25, HMPPS reported 26,348 drug find incidents, 25% more than the previous 12 months. The proportion of adult male prisoners reporting that it is easy to get illicit drugs in prison increased from 24% in 2021-22 to 39% in 2024-25. Two recent developments present growing threats: the availability of novel substances such as synthetic opioids has increased – these are more potent in smaller quantities than traditional drugs, harder to detect and easier to convey into prisons; secondly, criminals are increasingly using drones to convey drugs into prisons, with drone sightings increasing by more than 750% between 2019 and 2023 and by 43% between 2023-24 and 2024-25 (paragraphs 1.5, 1.10 and 3.2, and Figures 1 and 2).

6 HMPPS’s information on the availability of illicit drugs in prisons has limitations that undermine its ability to prioritise interventions. The type of prisoner population, location and physical attributes of a prison all affect the quantity of drugs in a prison and how they are smuggled in. It is inherently difficult to collect complete information on illicit activity, but HMPPS has a range of sources that could provide useful insights to help target its resources. This includes drug finds, prisoners reported as ‘under the influence’, prisoner surveys conducted by HM Inspectorate of Prisons, and drug testing in prisons. However, there are significant limitations with some data. For example, ‘under the influence’ data are now mandatory but are not yet collected, reported or shared consistently. Further, HMPPS has not published a robust estimate of the random mandatory drug testing (rMDT) national positive test rate since 2017-18, when the figure was 21%. This is due to insufficient testing volumes to ensure statistical validity, and limits to the range of substances detectable by the test as synthetic drugs evolve. Prison staff collate some of this information in local tactical assessments, but those assessments are focused on broader security considerations and do not seek to identify or understand trends or patterns of drug prevalence (paragraphs 1.8 to 1.13 and 3.4).

7 HMPPS has been trialling an innovative method of identifying drug prevalence which may help focus testing where it is most useful. Since 1998-99, HMPPS has carried out rMDT on prisoners every month, the full cost of which it estimated in 2023 was around £8 million a year. In 2024-25, HMPPS conducted 53,300 random mandatory drug tests but prison staff told us that these random tests were operationally resource-intensive. They considered that using constrained testing resources on targeted testing (for example, where staff had suspicions of drug use) was much more useful in managing prison operations. Since 2023, HMPPS has been trialling prison wastewater testing for traces of illicit drugs, which, if successful, could reduce disruption to the prison regime and reduce staff resources required (paragraphs 1.13 to 1.15).

The government’s leadership, funding commitments and prioritisation

8 The government’s commitment to tackling drug harms in prisons requires renewed funding and partnership arrangements. In 2021, the then government published a cross-government, 10-year strategy, From harm to hope, to tackle drug-related issues. This strategy included a significant component to tackle drug harms in prisons, with £114 million funding between 2022-23 and 2024-25. To oversee this strategy, the then government established the cross-government Joint Combating Drugs Unit (JCDU), including MoJ, DHSC and four other government departments. In addition, HMPPS and NHSE signed a National Partnership Agreement, setting out core objectives and priorities for tackling drug harms in prisons for 2022 to 2025. In early 2025, the government announced that NHSE would be abolished by 2027. Arrangements for commissioning healthcare in prisons after 2027 have not yet been confirmed. The current national partnership agreement was due to end in 2025 but, in January 2026, signatories agreed to extend it until 2027. The government has not announced dedicated funding for cross-government work to tackle drug harms from 2025-26 onwards (paragraphs 2.3 to 2.6 and Figure 5).

9 HMPPS has significantly underspent on two investment programmes that aim to reduce drug harms in prisons. Quantifying the total costs incurred by HMPPS in combatting illicit drugs in the prison system is impractical because so many of its business-as-usual activities serve multiple purposes. However, between 2019-20 and 2021-22, HMPPS spent only 75% of its £100 million security investment programme budget, with the largest underspend in gate security. HMPPS told us that the unspent funding was used to cover other operational activities. HMPPS was also allocated £114 million between 2022-23 and 2024-25 for prison-based and cross-cutting initiatives as part of the cross-government drug strategy From harm to hope. The actual budget was revised to £97 million to make savings and, of this, HMPPS spent only £67 million (69%). Reasons for the underspend included delays to spending approvals in the first year, reducing the scope of some projects as part of its wider efficiency savings commitment, and delayed staff recruitment (paragraphs 2.2 and 2.6 to 2.10, and Figures 6 and 7).

10 NHSE spending on mental health and substance misuse treatment in prisons in England was lower in real terms in 2024-25 than it was in 2020-21. The combined spend on mental health and substance misuse treatment in prisons in England, not including primary care staff costs, was £226.4 million in 2024-25. Looking at the last five years, this represents a cash increase compared with the £202.9 million spent in 2020-21, but a real-terms decrease of 5%. NHSE was required to make 1% efficiency savings each year in the period. NHSE does not identify separate costs for substance misuse treatment and mental health treatment, as the two are linked. We estimate that about 39% of the combined expenditure (£88.8 million in 2024-25) relates to substance misuse treatment. An increasing proportion of prison healthcare funding is drawn from in-year bids to NHSE’s contingency fund (paragraphs 2.13 and 2.15, and Figures 8 and 9).

11 NHSE does not use regional health needs assessments to decide its funding allocations. Health needs within a prison population depend on a range of factors, including gender, age and churn in prisoners. Each of the seven NHSE regions commissions prison-level health needs assessments. However, the scope, coverage and frequency of assessments, including coverage of drug treatment and recovery, vary, so cannot reliably be used to inform trends in changing needs or understand differences between prisons. Instead, NHSE allocates funding to regional commissioners based on historic contract values, adjusted by an annual NHSE funding uplift and efficiency reduction (paragraphs 1.16 and 2.14, and Figure 4).

12 There is significant regional variation in NHSE spending on substance misuse treatment. We found that in 2024-25, the London region spent around 72% more per prisoner than the East of England on substance misuse treatment. NHSE has not investigated this variation. It does estimate the annual cost per prisoner of all health services, which ranges from £5,000 to £12,000 depending on each prison’s function, location, and prisoner demographics (paragraph 2.14 and Figure 9).

How effectively resources have been used

13 HMPPS has sought to reduce the quantity of drugs getting into prisons, but has been too slow in responding to urgent threats, leaving some prisons vulnerable. HMPPS seeks to disrupt conveyance routes for drugs using a range of physical solutions such as enhanced scanning and window grilles as well as counter-corruption measures. But prison governors we spoke to told us that they do not have sufficient resources to respond to threats in an agile way. We identified examples of broken security equipment not being repaired and work to improve window security taking several years. Maintenance work must balance competing priorities such as maximising use of cells and undertaking security improvements, which can make it difficult to respond to urgent threats. In 2025-26, HMPPS committed around £40 million of investment to high-risk prisons for security measures, such as window grilles and netting, to counter ingress from drones (paragraphs 2.11 and 3.3 to 3.6).

14 Factors such as the physical constraints of prison buildings, prison maintenance backlogs and lack of staff training reduce the effectiveness of HMPPS’s actions to prevent drugs from entering prisons.

The physical design, age and poor condition of some prisons make them vulnerable to drug ingress, particularly older prisons and listed buildings. For example, it can be hard to implement enhanced gate security if the physical space is not well suited. The maintenance backlog across the prison estate has also doubled from £0.9 billion to £1.8 billion between February 2020 and September 2024 (paragraphs 3.4 and 3.5).

MoJ has identified staff shortages, lack of training, and retention as main barriers to reducing ingress of drugs into prison. For example, an internal audit report found that 40% of sampled prisons did not hold complete and accurate training records for using technology such as X-ray body scanners, and around a third of prisons could not evidence that they had carried out quality assurance of searches (paragraph 3.7).

There are technological, regulatory, legal and health constraints limiting prisons’ ability to detect new drugs, use body scanners on individuals, or test legally privileged mail for the presence of drugs (paragraphs 1.10 and 3.9).

15 HMPPS’s evaluations of its initiatives to reduce demand for drugs are starting to provide insights into what works. HMPPS has a long-term programme for evaluating the interventions funded by the drug strategy. Two major initiatives are Incentivised Substance Free Living (ISFL), drug-free living areas offering enhanced privileges for abstinence; and Drug Recovery Wings, designed for people dependent on illicit drugs who wish to receive treatment. In 2024, a process evaluation of the ISFL initiative noted significant variation between the three prisons under review in the scheme’s implementation, including how they selected prisoners to participate and how they dealt with positive drug tests. A review of Drug Recovery Wings found that, while there was evidence of positive change, the scheme had not been implemented as intended. Overall, HMPPS does not yet know whether its interventions have achieved good value for money or been prioritised where they will have most impact. However, it is aware of differences in implementation and intends to explore which characteristics are most effective (paragraphs 3.12, 3.13, 3.15 and 3.16, and Figure 13).

16 NHSE commissioners have limited evidence to demonstrate that drug treatment services are improving or providing best value for money. There is a shallow market for healthcare and drug treatment provision in prisons, meaning in some cases competition for providers is limited. Commissioners can set local performance measures and thresholds appropriate to the prison. NHSE told us that it has a robust contract management process to address instances of poor performance, and regional commissioners hold regular contract review meetings with providers. We reviewed a sample of records from contract review meetings and found they varied in scope and coverage. NHSE shared an example of commissioners taking robust steps requiring providers to make service improvements in response to coroners’ reports following deaths in custody. We did not find much similar evidence of action triggered by routine contract monitoring, for example where prison staff had expressed dissatisfaction with the provider’s performance. NHSE told us that commissioners do require improvement actions where necessary from concerns raised informally, although it accepted there was little supporting documentation (paragraphs 3.17 and 3.18).

17 Capacity pressures and a lack of alignment between performance metrics for prison and health staff are hindering effective joint working. NHSE regional commissioners report to NHSE nationally where prison operational pressures are adversely affecting healthcare delivery. In February 2025, NHSE commissioners reported serious pressure on healthcare delivery in 35 prisons, of which 14 were “very likely to result in harm to patients”. In 2024-25, NHSE recorded nearly 160,000 substance misuse appointments as ‘Did Not Attend’ (DNA), around 35% of all appointments. This can be for a variety of reasons, including the prisoner choosing not to attend, but has the potential for negative impacts on people’s health and wellbeing, the efficient use of health and prison staff resources, and the prison regime. Moreover, DHSC data show that in 2024-25, 24% of prisoners with potential substance misuse needs waited over three weeks for a triage assessment, following reception screening, although the reasons for this are not recorded. Prison governors’ performance is currently assessed on metrics such as education and purposeful activity rather than on facilitating prisoner access to drug treatment services, which can lead to a risk that these may be seen as lower priority. Conversely, some prison governors told us they lacked an adequate mechanism for engaging with health service performance, including what they believed to be underperformance (paragraphs 1.17, 3.18, 3.21 to 3.23 and 3.26).

Conclusion

18 Illicit drugs in prison pose significant challenges to successful offender rehabilitation, prisoners’ physical and mental health, the safety of staff and prisoners, and the stability of the prison environment. Tackling drug harms in prison involves restricting the supply of drugs into prison and supporting people in prison to reduce their drug misuse, both through drug treatment and recovery services and by creating a prison environment that incentivises sustainable drug-free living. This works best where there is good liaison between HMPPS and health services, with a shared understanding of need and well-aligned incentives for staff to support prisoners’ treatment and recovery. However, in a context of wider pressures on prison capacity, prison staff reported they lacked the influence needed to improve health-related services, while NHS staff did not always feel sufficiently involved in decisions on prison operations and were reliant on prison staff to enable those services to be delivered safely.

19 It is impractical to calculate a precise cost of tackling drug harms in prisons, making it impossible to assess overall value for money of drug treatment and recovery. However, HMPPS significantly underspent budgets intended for security improvements and initiatives to support prisoners. We also heard prison staff voice their frustration at the slow pace of urgent repairs and improvements. Meanwhile, our estimate is that drug treatment funding has decreased in real terms. Better performance information, continued willingness to innovate, continued learning from robust evaluation and, above all, a renewed commitment to cross-government partnership working will be essential for the government to direct resources to where they will have greatest impact.

Recommendations

a To reduce drug availability and get better value for money from spending on drug treatment, HMPPS should respond with more urgency to identified security weaknesses at specific prisons, including broken windows or inadequate window grilles that currently allow drone access into prisons, specifically by:

allowing senior operational leaders to bid for responsive security investment to ensure available funds can be used; and

reviewing the maintenance contract to increase responsiveness and flexibility where there are urgent security-based works.

b There are many factors influencing drug supply and use in prisons, but HMPPS and NHSE require better information on prevalence and need to prioritise funding.

HMPPS should consider how it might use its drug testing resources to best effect, to get optimal information on prevalence and treatment need from the range of available drug testing options (including individual testing options and wastewater testing). It should use these resources to inform operational decisions, monitor and compare prison performance, and influence decisions on security and health treatment.

MoJ and HMPPS should share ‘under the influence’ data more consistently within and across prisons, and with DHSC and NHSE. All the partner organisations should use this information to understand changes in the prevalence of drug misuse, assess risks, and measure the impact of ‘under the influence’ instances on other services.

c To enable health commissioners to ensure they are getting value for money from drug treatment and recovery services they are paying for, the commissioners should:

refocus health needs assessments (HNAs) to inform commissioning and funding allocation decisions. These HNAs should include a specific focus on drug treatment and recovery needs of local populations;

refine standardised costing formulae to benchmark the cost of drug misuse services that takes account of different needs in different prisons, including the prevalence and type of drugs, and variation in prison population (such as age, gender and churn); and

include costed key performance indicators in contracts that test whether providers are delivering value for money for those services.

d As DHSC redesigns responsibilities for health in prisons, HMPPS and relevant health bodies should renew and strengthen partnership arrangements, both nationally and locally. These should support better alignment of incentives to shared goals on health-related interventions, for more effective performance management and partnership working, including increased information sharing.

e HMPPS and NHSE should draw on robust evaluation to understand what works and encourage best practice.

HMPPS should conduct a programme of evaluations of the relative success of security measures to restrict ingress of drugs. It should use the findings of this work to support evidence-led training and development for staff.

HMPPS and NHSE should continue their programme of evaluations of measures to tackle drug misuse, including drug strategy investment funding such as Incentivised Substance Free Living. They should draw on the findings of this work to improve understanding about factors supporting and detracting from successful implementation, and take these factors forward in any further rollout of schemes to tackle drug misuse in prisons.

Part One

The government’s understanding of the scale and nature of drug misuse in prisons

1.1 This part sets out:

the harms caused by illicit drugs in prison and the worsening trend; and

the government’s approach to understanding the scale and nature of the problem.

The risk of harm from drugs in prisons

1.2 In April 2025, half of prisoners had an identified drug problem, which we estimate represents approximately 40,000 people in prisons in England and Wales.1 Misuse of illicit drugs in prison is a risk to prisoners’ physical and mental health, well-being and personal safety, and can even lead to hospitalisation or death. Between December 2022 and December 2024, the Prisons and Probation Ombudsman investigated 833 deaths, of which 136 (16%) were drug-related.2 Prison staff can also be harmed by incidental direct exposure to drugs while carrying out their duties.

1.3 The conveyance, supply and use of illicit drugs increase risks to the safety and stability of the prison regime, which can put both prisoners and prison staff at risk. The value of drugs inside prisons is far higher than in the community, creating powerful incentives for organised criminal groups to seek ways to convey drugs (and other illicit items) into prisons. There is often an illicit prison economy of drugs and other items, which can create debt that can lead to assault, extortion or self-harm. Drug-related violence risks injuring prisoners and staff, and disrupting both the prison regime and rehabilitative healthcare provision. Illicit drugs can create a violent cycle whereby violent or unstable prison conditions can fuel demand for drugs as a coping mechanism.

1.4 Drug misuse is associated with offending and reduces the chances of rehabilitation. In 2023, the previous government commissioned an independent review of drug treatment in prisons led by Dame Carol Black. She reported that around 50,000 people serving short prison sentences each year are there because of drug addiction and the crimes they commit to fund it. For these people, prison should be an opportunity to engage in rehabilitative activities. However, the review described a system with far too many drug-dependent individuals in prisons, who frequently reoffend after leaving prison.3

1.5 Available data indicate that illicit drugs in prisons represent a substantial and worsening problem (Figure 1). As part of its prison inspections, HM Inspectorate of Prisons (HMIP) surveys prisoners about their treatment and conditions. In 2024-25, 39% of survey respondents in adult male prisons said it was easy to get illicit drugs in their prison, an increase from 24% in 2021-22 (Figure 2).4 Further, 11% of men and 19% of women reported they had developed a drug or alcohol problem since entering that prison, an increase from 8% and 10%, respectively, since 2021-22. The nature of the threat can change quite quickly. The number of finds of novel psychoactive substances, such as synthetic opioids, in prisons increased by 45% between 2023-24 and 2024-25. These new drugs are a key concern as little is known about the serious harms caused by their use. They are more potent in smaller quantities than traditional drugs, easier to convey and harder to detect. The risk that criminals will use drones to smuggle drugs into prisons has been rising significantly, with drone sightings around prisons in England and Wales increasing by more than 750% between 2019 and 2023, and by 43% between 2023-24 and 2024-25.5 An increase in the number of drone incidents does not necessarily indicate more drone incursions, it may simply indicate more reports. However, drones represent a substantial risk because, compared with other routes, drones have the potential to deliver relatively large packages of illicit items in a very targeted way.

1.6 The Ministry of Justice (MoJ) and Department for Health and Social Care (DHSC) are responsible for tackling supply and use of illicit drugs in prisons, delivered through HM Prison and Probation Service (HMPPS) in England and Wales, and by NHS England (NHSE) in England.6 HMPPS, an executive agency of MoJ, has operational responsibility for prisons in England and Wales. It plays a crucial role in preventing drugs from entering prisons, helping to keep prisons safe, and has several initiatives aimed at tackling drug misuse and supporting recovery in prisons. HMPPS also works with the National Crime Agency (NCA) and the police to prevent organised crime groups smuggling drugs into prisons. NHSE, an executive non-departmental public body of DHSC, is responsible for commissioning healthcare services in prisons. Healthcare providers deliver substance misuse treatment and recovery services. Commissioning responsibility is expected to pass to Integrated Care Board commissioners when NHSE is abolished in 2027.

Understanding the scale and nature of drug misuse

1.7 To manage the risks created by drugs in prisons and prioritise resource allocation effectively, justice and health services need a good understanding of how drugs get into prisons, their prevalence inside prisons, and prisoners’ drug treatment needs.

HMPPS’s understanding of how drugs enter prisons

1.8 Criminals use various ways, including ‘throwovers’, smuggling by visitors or staff and, more recently, drones, to get drugs into prisons.7 HMPPS cannot reliably quantify the volume of drugs getting into prison via different routes as, by its nature, this is illicit activity, but it has a good understanding of risk factors affecting how drugs get into prisons. Overall, the use of drones appears to have been increasing rapidly, and HMPPS believes it will continue to do so as commercially available drones become cheaper. But the vulnerability of prisons to different routes is to some degree dependent on their location and function. For example, prisons in some rural locations may be more susceptible to drone activity due to the large areas within which a drone operator may conceal themselves. Prisons which serve a reception function, or have a high volume of prisoner transfers, tend to be more susceptible to drugs entering through the prison gate, concealed by prisoners or in their possessions. Common routes into prison may also change over time if one entry route is closed, as criminals will seek to exploit an alternative. Each month, prisons produce local tactical assessments (LTAs), designed to highlight emerging security risks and inform local responses. These assessments include indicators such as drug finds and positive test rates, although their focus is wider than drugs. However, LTAs do not monitor trends in these metrics, meaning they only give a snapshot of drug prevalence at a point in time.

Understanding the prevalence and type of drugs in prison

1.9 There are several ways to help identify the quantity and type of drugs in prisons. None of these data sources represents a complete picture by itself. While LTAs provide a snapshot of drug prevalence, we did not see evidence of HMPPS or NHSE collating, sharing and using the range of measures such as these to compile a better understanding of drug prevalence and trends to make agile interventions.

Drug finds

1.10 In 2024-25, HMPPS reported 26,348 drug find incidents, an increase of 25% since 2023-24.8 However, HMPPS recognises that drug finds are broadly proportionate to search activity, and do not necessarily reflect the underlying prevalence of drugs. Published data show that, on average, between 2022-23 and 2024-25, prison staff categorised 48% of reported drug finds as either ‘other’ or ‘unknown’. This may in part be due to the way drug finds are reported, and the emergence of novel synthetic drugs that can be difficult for prison staff to identify. In April 2023 HMPPS introduced a national drug seizures contract which allows prisons to send physical drug finds for laboratory testing to identify their contents.

‘Under the influence’ observations

1.11 Since January 2025, HMPPS has required prisons to report monthly any instances where a prisoner was observed to be under the influence of drugs. We found, however, that the data remain variable, with no standardised way of reporting or assuring information. Some prisons reported hundreds of ‘under the influence’ instances in one month, and zero in other months. This could reflect volatile drug availability, or inconsistent reporting. In some months, around a third of prisons did not submit a return. HMPPS told us it is working to improve the reliability and consistency of reporting across its prisons.

Survey data

1.12 HMIP survey data between 2021-22 and 2024-25 suggest that the prevalence of illicit drugs has been increasing but is not equally distributed across the prison estate. For example, prisoners in open prisons are 10 percentage points less likely to report drugs being easy to get, compared with those in training and/or resettlement prisons.

Testing for drugs

1.13 Since 1998-99, HMPPS has carried out random mandatory drug testing (rMDT) on prisoners every month, the full cost of which it estimated in 2023 was around £8 million a year. In 2024-25 it conducted 53,300 tests (Figure 3). HMPPS requires each prison to conduct rMDT on at least 5% to 10% of their population each month, depending on the number of prisoners, and aggregates results to form a national positive test rate. However, HMPPS has not published a robust estimate of the rMDT national positive test rate since 2017-18 when the rate was 21%, for the following reasons.

Not enough prisons have tested sufficient volumes for the results to be statistically valid. In 2024-25, HMPPS would have needed to carry out more than 3,000 additional tests to produce a robust national estimate of the positive test rate. HMPPS told us that staffing pressures are the main reason behind the lower testing volumes, and staff told us these tests are operationally resource-intensive.

Limits in the range of drugs detected by the test mean the results are incomplete. Between 2017-18 and 2019-20, the positive test rate fell by around seven percentage points. HMPPS attributes this to an increased use of new psychoactive substances, which were not detected by the test. HMPPS has since added new drugs to the testing panel, but some gaps still remain.

Alternative approaches to drug testing

1.14 HMPPS also carries out other types of drug testing. These may be used, for example, when staff have a suspicion that a prisoner has taken drugs, or when a prisoner may be in a role with greater access around the prison. These types of testing cannot be used to estimate prevalence, since they are targeted, but staff in prisons told us they found them more useful than random tests in managing prison operations such as deciding who to release on temporary licence. However, HMPPS told us that, with the resources available, it could not do these more targeted tests as often as it would like.

1.15 Although random drug testing is HMPPS’s primary means of measuring prevalence, between August 2023 and March 2025, HMPPS trialled an innovative pilot to test the wastewater of 41 prisons in England for traces of drugs. Wastewater-based surveillance (WBS) testing can detect all substances which HMPPS includes on the mandatory drug test and also new synthetic opioids. WBS testing can give a whole-prison view of prevalence with minimal disruption to the prison regime, and can often be conducted outside the prison walls. In 2024-25, HMPPS spent £3.2 million on this pilot, implying a higher total cost than the current random mandatory testing regime if rolled out to all prisons. However, there may be potential for long-term savings, due to fewer staff involved in testing. Early findings from the pilot show that prevalence data from WBS testing largely align with rMDT results, and that in 29 out of 41 sites HMPPS could take wastewater samples with minimal disruption to the prison regime. However, despite these promising results, some barriers to a wider rollout of WBS remain, such as where prison infrastructure can make it difficult to access wastewater sampling. Internationally, prison services have also conducted smaller WBS pilots in some other countries, including France, Spain and Australia.

Understanding drug treatment and recovery needs of the prison population

1.16 NHSE regions commission health needs assessments (HNAs) periodically to give a snapshot of the health needs of a prison population at that time. Health needs within a prison population depend on a range of factors, including gender, age and churn in prisoners. HNAs focus on the prevalence of long-term illnesses and mental health needs but can also include drug treatment needs and recommendations for service improvements. Published health guidance recommends that NHSE regions commission full HNAs every three years, with annual refreshes in between. However, we found that HNAs have not been carried out at some prisons for up to five years. NHSE regions do not design HNAs consistently, with the data collected on drug treatment and recovery varying (see Figure 4). This means that NHSE cannot collate these assessments to create a national picture of need.

1.17 When prisoners arrive into custody, they should receive a reception screening by healthcare providers to assess their physical and mental health needs. Prisoners with potential substance misuse needs are referred to triage assessments to identify the most suitable treatment. DHSC data show that on average, in 2024-25, 76% of triage assessments took place within three weeks of the reception screening, an internal target set by the department. However, timeliness varies between prisoners who are taken directly into custody (from court), at 88%, and those transferring from another secure setting, at 61%. DHSC told us this is because those who arrive from another prison are less likely to engage in treatment within three weeks than those arriving directly into custody. In some prisons, significant churn in the prison population creates high demand for these assessments, with timeliness suffering as a consequence.

1 This figure is based on data from unpublished Ministry of Justice management information systems. These data have not undergone the full quality assurance process required for official statistics and may be subject to further revisions.

2 Prisons and Probation Ombudsman, evidence submitted to the 2025 Justice Select Committee inquiry on tackling drugs in prisons.

3 Dame Carol Black (independent advisor to the government on drugs), evidence submitted to the 2025 Justice Select Committee inquiry on tackling drugs in prisons.

4 The number and types of prisons that HMIP inspects changes each year, meaning figures are not directly comparable across years.

5 Drone incidents include all drone sightings, including crashes, recovery, conveying unauthorised articles into the establishment restricted fly zone, or where the drone is believed to be photographing prisoners, staff or parts of the building’s fabric. As such, drone incidents do not correspond directly to the entry of drugs or other illicit items.

6 Healthcare in Wales is a devolved function, provided by NHS Wales, and is not covered by this report.

7 A throwover is where someone throws an illicit item over the prison wall into the prison.

8 A single incident can represent a drug find of any quantity of drugs, or of more than one type of drug.

Part Two

Funding decisions, prioritisation and accountability

2.1 This part sets out:

the government’s commitments and leadership on reducing harm from drugs in prison;

the resources HM Prison and Probation Service (HMPPS) and NHS England (NHSE) spend on tackling drug harms in prisons; and

how HMPPS and NHSE prioritise and allocate funding.

2.2 It is inherently difficult to quantify how much public money HMPPS and NHSE spend specifically tackling drug harms in prisons. Some measures to tackle drugs also contribute to other goals, making that element of funding impractical to disaggregate. For example, routine spending on security helps to stop weapons, money and mobile phones entering prisons, as well as illicit drugs. Equally, treatment for drug dependency is often part of a wider support package to improve prisoners’ mental and physical health.

The government’s commitments and leadership

2.3 As we reported in 2023, tackling illegal drugs is a cross-government problem, linked to wider criminal activity in prisons and the community.9 In 2021, the then government published From harm to hope, a 10-year strategy to tackle illegal drugs and related harm.10 To oversee this strategy, the government established the cross-government Joint Combating Drugs Unit (JCDU), of which the Ministry of Justice (MoJ) is a key departmental sponsor, alongside the Department of Health & Social Care (DHSC) and four other government departments.11 Tackling drug harms in prisons is a component part of the strategy. Figure 5 sets out the main roles of the bodies involved in tackling drugs in prisons.

2.4 The JCDU has no formal powers and does not direct departmental operations but focuses on coordinating the work of government bodies and overseeing local Combating Drugs Partnerships.12 For example, it drew together a joint funding bid for the 2021 Spending Review to cover the first three years of the drug strategy across government. This funding related to 2022-23 to 2024-25, and as yet no further dedicated funding has been announced for 2025-26 until the end of the strategy in 2031. HMPPS told us that funding for continuing drug strategy projects into 2025-26 was rolled over from the previous year, and that maintaining current levels of delivery into 2026-27 and beyond was subject to ongoing allocation decisions. JCDU also coordinates work across the six departments to evaluate the impact of drug strategy interventions.

2.5 There are separate HMPPS and NHSE accountability and decision-making lines for substance misuse in prisons.

HMPPS manages and oversees prison-based initiatives supported by drug strategy funding, such as physical security measures and Incentivised Substance Free Living (ISFL) facilities, through the Drug and Alcohol Delivery Board.13 This board meets monthly and includes officials from HMPPS and MoJ who lead initiatives to address drug and alcohol use across prison and probation. The board reports to several internal boards at HMPPS, including the Rehabilitation Directorate Portfolio Board, which has a broader remit and is responsible for a range of issues outside substance misuse.

NHSE has statutory responsibility for health treatment for substance misuse in prisons. There are also shared governance structures that oversee partnership working between the health and justice systems. Both HMPPS and NHSE are signatories to a National Partnership Agreement, which covers custody and people on probation and sets out shared high-level objectives. The cross-government Health and Justice Strategic Partnership Board is ultimately responsible for ensuring that the partnership meets its strategic goals. Members include senior officials from MoJ, DHSC, NHSE, HMPPS and the Home Office. In early 2025, the government announced that NHSE would no longer exist from 2027. The current national partnership agreement was due to end in 2025 but, in January 2026, signatories agreed to extend it until 2027 while a successor agreement is prepared to reflect new health commissioning arrangements.

Resources available to fund prison services

2.6 Much of HMPPS’s business-as-usual spending has an element that relates to tackling drug harms in prisons that cannot be quantified. For example, staff facilitate prisoners moving around the prison as part of the routine prison regime, but there are no specific data on how much it costs to escort them to drug treatment appointments. However, since 2019, HMPPS has received two tranches of dedicated funding, much of which was intended to tackle drug harms.

In August 2019, MoJ announced an investment package of security measures called the security investment programme (SIP). The formal budget allocation of £100 million was agreed in March 2020, including expenditure already incurred during 2019-20.

In December 2021, the government announced £114 million to tackle drugs in prisons over three years between 2022-23 and 2024-25 as part of a wider £900 million funding package to progress the aims of its drug strategy From harm to hope.

Security investment programme

2.7 HMPPS underspent against its original SIP budget of £100 million (Figure 6), with expenditure of £75 million. The largest underspend (by value) was in additional gate security. HMPPS cited delays in increasing staff numbers, and failure to procure baggage scanners as the reasons for its underspend. HMPPS told us that the unspent funding was used elsewhere to cover other operational activities. Some planned investments, such as a new digital forensics laboratory, were not delivered during the programme, and HMPPS had to fund the work separately from other budgets, including drug strategy funding. The laboratory opened in January 2025, but the delays limited HMPPS’s ability to review digital evidence of drug conveyance.

Drug strategy funding

2.8 HMPPS also did not spend all of its drug strategy funding. MoJ initially allocated £114.4 million to HMPPS for the period 2022-23 to 2024-25. Of this, £49.3 million was for 17 projects entirely within the prison estate and £65.1 million was for 11 cross-cutting projects that covered both prison and community settings. However, department-wide requirements to make savings reduced the budget to £97.2 million.

2.9 Over the three years covered by the funding, HMPPS only spent £67.3 million, representing 59% of the original funding or 69% of the revised budget (Figure 7). These underspends were not equally distributed. For example, while HMPPS spent all of its revised budget on its testing programmes, it spent less than half of the project budget on 16 of the 28 prison-related projects included in the drug strategy.

2.10 We identified the following reasons for underspends.

Late approvals: Despite the government announcing funding in December 2021, and HMPPS funding projects from financial year 2022-23 onwards, ministers did not sign off the budget until July 2022. This meant that the first year of expenditure was significantly truncated: in 2022-23 HMPPS spent only 31% of its budget for that year.

Reduced scope: HMPPS had originally committed to a greater number of ISFL facilities and Drug Recovery Wings and wanted a drug strategy lead in every prison in England and Wales. However, HMPPS scaled back the further rollout of Drug Recovery Wings so only seven of the planned 18 were launched. As at October 2025, there were 87 ISFL facilities and 91 drug strategy leads across 124 prisons, although only 54 of those drug strategy leads are centrally funded by the drugs strategy through the HMPPS Drug and Alcohol Group.

Delayed recruitment: It took longer than planned for HMPPS to recruit into a number of roles funded by the drug strategy, for example drug strategy leads. HMPPS told us this was in part due to recruitment controls impacting headquarters teams as well as the length of time vetting can take depending on the type of prison and role requirements.

Unforeseen complications: Some HMPPS projects were novel. For example, HMPPS planned to roll out naloxone, a potentially life-saving drug used to treat opioid overdose, so prison officers could administer it in medical emergencies. However, HMPPS did not have the required licence to buy restricted medication, and told us that it negotiated to buy through the NHS until relevant regulations were changed.

Lack of progress on some key projects. HMPPS did not deliver its new digital forensics laboratory within the funding period, despite the project being started under the security investment programme in 2020-21.

Wider capital funding

2.11 Aside from specific funding initiatives to tackle drug harms in prison, HMPPS can spend some of its annual capital budget on improving security. HMPPS told us that it could not fund all the projects that prison staff asked for because it prioritises investments according to their impact and risk mitigation, as well as affordability and deliverability. However, there may be other competing priorities for capital funding. For example, in December 2024 HMPPS estimated it would cost £1.5 billion to complete essential fire safety improvements to prison cells. HMPPS allocates each prison region a portion of the national annual capital budget, within which the region must then prioritise investments, including security, drawing on advice from HMPPS Security Directorate as necessary. In 2025-26, HMPPS committed around £40 million to high-risk prisons for additional drone security such as window grilles and netting.

Resources available to fund NHS services

2.12 People in prison have a statutory right to health services equivalent to those available in the community. NHSE told us it takes an integrated approach to health care provision in prisons and does not have a separate budget for drug treatment services. Under current arrangements, commissioning decisions for individual prisons, or groups of prisons, are delegated to seven regional commissioners. Some health service providers offer integrated services, and some subcontract drug treatment services to specialist providers including third-sector organisations. We did not undertake a comprehensive review of NHS commissioning as part of this study. However, the example of bid evaluation criteria we saw included weighted criteria for measures of service delivery, clinical governance and value for money, including pharmacological and psychosocial care and continuity of care in the community. NHSE told us that there is no national standard set of criteria for bid evaluation.

2.13 NHSE collates national data from annual financial returns submitted by regional commissioners. It told us it did not consider it meaningful to identify the specific cost of drug misuse treatment because of overlap with other costs, including mental health interventions. The combined spend on mental health and substance misuse treatment in prisons in England, not including primary care staff costs, was £226.4 million in 2024-25.14 Looking at the last five years, this represents a cash increase compared with the £202.9 million spent in 2020-21, but a real-terms decrease of 5% (Figure 8). NHSE was required to make 1% efficiency savings each year in the period. We estimate, however, by allocating direct salary costs and the equivalent proportion of indirect costs reported by the regions, that in 2023-24 NHSE spent £88.8 million on substance misuse treatment, around 39% of the combined cost of substance misuse and mental health treatment. In 2025, NHSE allocated an additional £7 million from a central fund to address needs for drug treatment. This included increasing access to long-acting buprenorphine, a prescription medication used in drug treatment that is not routinely available in all prisons.

Baseline funding

2.14 NHSE allocates baseline funding to regional commissioners based on historic contract values, adjusted by an annual NHS funding uplift and an efficiency reduction. Regions can propose changes to their regional allocation to provide for changes, such as changes in the prison population or changes to prison functions. NHSE does not use regional health needs assessments to make funding allocations. NHSE estimates that the cost of all health services per prisoner, including substance misuse treatment, falls between £5,000 and £12,000, depending on each prison’s demographics, function and location. Costs are typically higher in female prisons, prisons with older populations, and prisons where there is a relatively high turnover rate of prisoners entering and leaving the prison. We estimated that, in 2024-25, the London region spent 72% more on substance misuse treatment per prisoner than the East of England (Figure 9). However, NHSE has not investigated this variation.

In-year funding

2.15 Regional commissioners can bid for additional in-year resources from a national contingency fund to respond to significant changes in demand because, for example, of new temporary accommodation or unanticipated changes in prison function. Additional approved in-year funding for mental health and substance misuse treatment increased from £7.1 million in 2021-22 to £27.0 million in 2025-26 (Figure 10), and in-year funding has become an increasingly high proportion of total funding for these services.

The estimated overall cost of tackling drug harms in prison

2.16 Figure 11 summarises our estimate of the spending that, in whole or in part, HMPPS and NHSE use to tackle drugs in prison. Some costs known to be related to drug incidents are not quantifiable. A good example is ‘code blues’, when an ambulance is called to a prison for a medical emergency, for instance when a person has overdosed. NHSE also incurs costs for prescription medication relating to drug addiction within the cost of primary care services. For example, NHSE collects data on the number of people receiving opioid substitution treatment but does not separately measure the cost of this medication. We have not attempted to quantify externalities such as staff injury or sickness resulting from dealing with drug issues.

9 Comptroller and Auditor General, Reducing the harm from illegal drugs, Session 2022-23, HC 1864, National Audit Office, October 2023.

10 HM Government, From harm to hope: a 10-year drugs plans to cut crime and save lives, December 2021.

11 The Joint Combating Drugs Unit also sits across the Department for Work & Pensions (DWP), Ministry of Housing, Communities & Local Government (MHCLG), Department for Education (DfE) and Home Office.

12 Recognising the importance of local service delivery to achieving the strategy’s outcomes, the government asked local areas to create new Combating Drugs Partnerships to bring together relevant organisations and provide a single point of contact for central government.

13 ISFL facilities are drug-free living areas offering enhanced privileges for abstinence.

14 HMPPS is responsible for prisons in England and Wales. As health is a devolved function, health services in Wales are commissioned by NHS Wales, and these figures relate to spend in England only.

Part Three

How effectively resources have been used

3.1 This part sets out:

how effectively HM Prison and Probation Service (HMPPS) has used resources to strengthen security and tackle ingress risks;

what HMPPS has done to help reduce demand for drugs in prison and promote a drug-free environment;

how effectively NHS England (NHSE) has used resources to provide drug treatment services; and

the barriers to effective partnership working.

HMPPS actions to reduce drugs entering prisons

3.2 HMPPS understands the nature and broad trends associated with drugs in prisons, particularly the risks of drones and of new substances like synthetic opioids. HMPPS coordinates activity nationally through a National Prison Control Strategy, drawn from Local Tactical Assessments (LTAs) compiled by prisons as a snapshot of local risk. LTAs do not seek to explain root causes or trends over time, so do not analyse which mitigations are most effective. The national strategy aims to identify and prioritise security risks and actions to address them. For example, in May 2024, HMPPS developed a synthetic opioid response plan to coordinate efforts across health, justice, and law enforcement bodies. However, the escalation of risks associated with drone activity has been comparatively slow. HMPPS first added a specific risk to its risk register on drugs entering prisons, particularly by drones, in January 2025, although it had been recording an increased number of drone sightings for six years by that point. It entered this risk at the maximum possible risk score of 25.

3.3 HMPPS seeks to disrupt conveyance routes by a range of measures (Figure 12), including the following:

Gate security for people and property entering the prison: HMPPS judges the main conveyance route to be through post not being searched effectively, as well as poor quality of prisoner, visitor and staff searches. Under the security investment programme HMPPS installed 74 new X-ray body scanners, and there are now 98 scanners across 95 prisons in the closed male estate. It has implemented enhanced gate security in 49 prisons, combining new electronic security measures, such as archway metal detectors and baggage scanners, with additional protocols for physical searching of people entering the prison.

Improving physical building security of walls and windows such as installing window grilles and nets: This is intended to make it harder for drugs to enter through drones and/or throwovers.

Intelligence-led corruption investigations: During 2024, HMPPS received 113,000 intelligence reports regarding staff corruption, 17% more than the previous year, and the highest recorded. HMPPS assesses that serious organised crime groups are the largest cause of staff corruption, which they can use to convey illicit drugs into prisons. HMPPS’s Counter Corruption Unit opened 79 cases between January and March 2025.

Seeking new legislation, regulation or technology: HMPPS has also sought to use legislative measures such as banning drone operation within 400 metres of a prison boundary, and is exploring innovative ways to reduce drug ingress via drones (see paragraph 3.10).

Investing in response to urgent need

3.4 The prison estate is often ill-suited for security improvements. For example, most prison windows, particularly in older prisons, were not designed to prevent smuggling via drones, and some prisons are listed buildings which constrains improvements. The physical space needed for enhanced gate security also limits its implementation at some prisons. Some participants in an HMPPS evaluation reported that HMPPS’s consultation with prisons on the suitability of additional gate security was insufficient. HMPPS has judged installation to be prohibitively expensive at some sites. In December 2025, HMPPS issued guidance on practical steps to increase resilience in the gate area to support those prisons that do not have the space or funding to implement full enhanced gate security measures.

3.5 HMPPS also faces practical challenges in tackling ingress of drugs because of constrained funding and limitations of its current maintenance contracts. There are many security improvements desired by prison staff to help reduce drugs getting into prisons, but these works compete with other urgent priorities, such as maximising use of cells, and may not be approved. Maintenance delays are a significant risk factor. The maintenance backlog across the prison estate doubled from £0.9 billion to £1.8 billion between February 2020 and September 2024.

3.6 HMPPS processes for allocating funding have been slow to respond to urgent needs, leaving some prisons more vulnerable than they should be. Governors have some discretion over local spend but told us they often do not have the resources to respond to threats in an agile way. We found an example of a prison that had been unable to X-ray scan prisoners’ luggage, a key route of drug ingress, because broken equipment remained unrepaired for many months. In January 2025, HM Inspectorate of Prisons (HMIP) reported that it was taking “far too long” to install secure windows and netting to prevent drones at HMP Manchester. HMPPS had approved funding in 2021 but, in 2025, told us it expected the work would take another seven years to complete.15 HMPPS has responded quickly to urgent notifications issued by HMIP but told us that this level of work would not be sustainable across all prisons without additional resources.

Staff capacity and training

3.7 All security mitigations require sufficient staff capability and capacity to operate effectively. HMPPS sets out its security policies and procedures through its National Security Framework. However, low staffing levels and insufficient training undermine their implementation. An evaluation by the Ministry of Justice (MoJ) of its security investment programme identified staff shortages and retention as the main barrier to reducing conveyance. More widely, HMPPS’s security audits have highlighted weaknesses in prisoner, staff and visitor searches, such as X-ray scanners not being used regularly due to staffing constraints. Many prisons also lack sufficient capacity to photocopy mail before passing it to prisoners, a method used to stop drugs impregnated into paper entering the prison. Insufficient staff training can also reduce the effectiveness of security mitigations. An internal audit report found that 40% of the prisons reviewed in the audit did not hold complete and accurate training records for relevant equipment, and around a third of prisons could not demonstrate they had carried out required quality assurance of searching activity.

3.8 Despite concerns regarding the role of staff corruption in drug ingress, in April 2025, HMPPS made a 50% reduction in the number of prevent managers working in its Counter Corruption Unit on preventing corruption. The Government Internal Audit Agency reported, also in April 2025, that HMPPS’s regional counter-corruption activity was inconsistent, due to vacancies and a recruitment freeze. A cross-government review in April 2024 found significant weaknesses in joint government working on serious and organised crime in prisons. HMPPS has stated that additional resource is critical to fully deliver on the report’s recommendations about improved intelligence sharing and developing a new shared operational framework.

3.9 Some legal or regulatory restrictions constrain HMPPS’s efforts to prevent drug ingress. For example, there are regulatory limitations which require that HMPPS only use body scanners on prisoners if they have intelligence or reasonable suspicion that they are conveying illicit items, to minimise radiation exposure. Prison staff will also need to be aware of any health conditions affecting individual prisoners. There are additional legal restrictions on HMPPS’s powers to open and test ‘rule 39’ mail, although HMPPS believes this is a high-risk conveyance route.16

Tackling increasing volumes of drones

3.10 HMPPS believes that a significant proportion of the sharp rise in drone activity in prisons is coordinated by organised criminal groups. Research in other European countries indicates a similar increase in the use of drones. Although HMPPS is improving perimeter and building security, it has assessed that these solutions alone will not be sufficient, and that some alternative options are likely to be unaffordable, or unsafe to use within a prison. The current pace of technological change also makes it difficult to invest effectively. In November 2025, MoJ launched an innovation challenge offering a £60,000 funding prize to develop proof of concept systems to detect drones designed by criminals to evade current detection methods available on the market.

Evaluating the effectiveness of security measures

3.11 Action to tackle one ingress route can lead to displacement to a different route. For example, an HMPPS evaluation identified that increased investment in gate security displaced drug conveyance to other routes, such as via drones and throwovers. As HMPPS cannot reliably quantify how many illicit items are conveyed into prisons, there have been no national or prison-level evaluations of how successful measures to counter ingress have been, or what the optimum balance of investment in security measures would be.

HMPPS interventions to reduce demand for drugs

3.12 Several strands of HMPPS’s drug strategy aim to reduce demand for drugs in prison and help people recover from drug addiction.

HMP Holme House trialled a whole-prison approach to drug recovery. It began in 2017 and aimed to reduce reoffending rates (paragraph 3.14).

Drug Recovery Wings and Incentivised Substance Free Living (ISFL) facilities both aim to provide a safe, drug-free environment focused on abstinence, recovery-based interventions, and community treatment and support upon release. Drug Recovery Wings exclusively house those dependent on illicit substances, whereas ISFL facilities reward abstinence with enhanced privileges, and can be offered both to people who have experienced addiction and those who have not (paragraphs 3.15 and 3.16).

3.13 It can take a long time until the results of initiatives are measurable, and HMPPS has a programme of process and impact evaluations in place (Figure 13). HMPPS gave individual prisons considerable freedom in implementing key initiatives like ISFL. While this allowed prisons to tailor them to the available buildings and facilities, it also means it will be difficult for HMPPS to fully assess the impact and value for money of its interventions in the short term. Instead, evaluations will seek to draw out and apply examples of what has worked well.

HMP Holme House drug recovery prison

3.14 The impact evaluation of Holme House was completed in 2025 and looked at reoffending rates after release. The evaluation could not be completed until enough prisoners had spent a year in the community after their release, to test reoffending rates. It found that prisoners who had been at HMP Holme House between 2018 and 2020 were more, rather than less, likely to reoffend after release than those at comparable category C prisons. The evaluators suggested that this result may have been because the hoped-for cultural change would take longer to achieve than the pilot allowed.

Incentivised Substance Free Living and Drug Recovery Wings

3.15 In 2024 MoJ’s process evaluation of ISFL noted significant variation between the three prisons in how they recruited prisoners to the ISFL scheme and how they dealt with positive drug tests. The process evaluation for ISFL suggested that the scheme had achieved mixed results, with two prisons seeing broadly positive results and one where the results were more ambiguous. A subsequent impact evaluation published in December 2025 concluded that, when run effectively, “there is a high probability that Incentivised Substance Free Living wings provide a more stable environment for prisoners … [and] cause prisoners to engage in fewer incidents of assault, self-harm, and disorder.”

3.16 A 2025 process evaluation of Drug Recovery Wings (DRWs) at six prisons concluded that, although the DRWs had not been implemented as intended, there was evidence of positive change. The evaluation suggested that DRWs had helped to improve the prison environment where they had been implemented. As a process evaluation, this study did not quantify the impacts of this initiative.

NHSE’s management of its drug treatment services

3.17 Performance indicators differ across provider contracts for drug misuse treatment and recovery, making it difficult to assess national performance on a consistent basis. NHSE regional teams choose both the measures and target value set for each measure, based on their view of the most important challenges in individual prisons. For example, reception prisons have higher turnover rates than training prisons so the target number of health screenings may be lower. Commissioners require local knowledge to interpret metrics collected because low volumes of drug treatment activity may not mean poor provider performance. Medical staff may, for example, be prevented from providing treatment because of security incidents in the prison, or because they may need to support emergency health responses (‘code blue’ incidents).

3.18 NHSE regional commissioners have limited ability to drive performance improvements with providers. NHSE regional commissioners told us that they would expect to receive multiple bids for a contract, but we also saw examples where there were no bidders or a single bidder for substance misuse treatment. A shallow market for healthcare and drug treatment provision in prisons can make it difficult for NHSE to remove a contract if performance is poor. NHSE told us that it has a robust contract management process to address poor performance. It said that NHSE regional teams hold regular contract review meetings with providers to discuss healthcare services in prisons and any escalation routes. We reviewed a sample of records from contract review meetings and found they varied in scope and coverage. In the cases we reviewed, we did not find evidence of NHSE using routine contract review meetings to require providers to take action on concerns or of how these meetings have, in practice, led to performance improvements. We did, however, find evidence that prison governors and staff had expressed dissatisfaction to NHSE about providers’ performance. NHSE shared an example of commissioners taking robust steps requiring providers to make service improvements in response to coroners’ reports following deaths in custody. We did not find much similar evidence of action triggered by routine contract monitoring, or in response to concerns raised by prison staff. NHSE told us that commissioners do require improvement actions where necessary from informal concerns, although it accepted there was little supporting documentation, as discussions are often not recorded, for sensitivity reasons.

Effective partnership working between HMPPS and NHSE

3.19 Helping prisoners with a drug treatment need requires effective partnership working between HMPPS and NHSE, both nationally and locally. Effective working would include the following: a shared set of objectives and performance measures; routine liaison on prison operations to enable prisoners to access healthcare; and sufficient information sharing between health and prison staff.

Alignment of objectives

3.20 Nationally, MoJ and the Department of Health and Social Care share a substance misuse dashboard which reports selected health- and justice-related performance metrics. Information shown includes, for example, the percentage of patients who received treatment and who did not return for treatment within six months. However, the data are very summarised; for example, it is not available at prison level. The lack of detail limits the value of the dashboard as a tool for NHSE and HMPPS to assess the effectiveness of drug treatment services in prisons.

3.21 At individual prisons, HMPPS and health staff liaise regularly about prisoners’ needs for drug treatment. However, a lack of alignment between performance metrics for prison staff and healthcare providers can create friction. Prison governors have overall responsibility for running their prisons and are accountable for how their prisons perform on a range of indicators, such as how much purposeful work and education activities prisoners undertake. Governors are accountable to Prison Group Directors and Area Executive Directors within HMPPS. However, while governors address issues that affect drug misuse, such as security, they are currently not assessed directly on their performance in facilitating access to drug treatment services. This creates a risk of giving healthcare appointments a lower priority than some other activities. To mitigate this risk, HMPPS told us that it will begin measuring attendance at internal healthcare appointments from April 2026. Equally, while local healthcare providers are accountable to NHSE regional boards on drug treatment services, there may be broader prison issues that negatively impact a prisoner’s care.

Barriers to effective drug treatment services

3.22 Issues affecting the prison and health systems, such as staff shortages and increased prisoner transfers due to an over-full prison estate, can make it more difficult for HMPPS and NHSE to comply with good practice to deliver effective interventions. An April 2025 Internal Audit report gave an example from HMP Humber, which had reported receiving several prisoners transferring from another prison, who arrived without a health assessment and that, while the sending prisons should be providing seven days’ worth of medication, this was often not the case. Delays accessing prescription medicine can lead prisoners to seek illicit alternatives.

3.23 One key role for HMPPS at individual prisons is ‘enablement’, or ensuring prisoners are able to access drug misuse treatment. This includes escorting prisoners to appointments, overseeing dispensing of medicines, and running a safe prison regime. NHSE regional commissioners report to NHSE nationally, by exception, where prison operational pressures are adversely affecting healthcare delivery. As at February 2025, NHSE commissioners reported serious pressure on healthcare delivery in 35 prisons, of which 14 were “very likely to result in harm to patients”. Commissioners also reported concerns over HMPPS enablement in 44% of prisons, and staffing issues in prison healthcare across all regions. NHSE told us that health workers go to see patients in their cells, but there was often no private consultation space available, the prisoners were unavailable, or the wing was locked down. The overall pressure has not improved since 2023, and performance had worsened in seven of the 14 most pressured prisons.

3.24 High volumes of ‘under the influence’ instances and ‘code blue’ emergency incidents among prisoners disrupt the prison regime, put pressure on health services and constrain planned health interventions. Clinical staff help respond to these incidents, which often require immediate medical attention and prolonged monitoring. Drug treatment service providers report that the frequency of these incidents is increasing, using resources that would otherwise support prevention and rehabilitation, and thereby reducing the quality of care providers can deliver.

Sharing information and monitoring

3.25 Drug strategy leads (DSLs) are prison staff with responsibilities for coordinating efforts to tackle drug misuse in prisons. HMPPS initially sought to recruit DSLs to every prison in England and Wales, but scaled back its plans because of funding constraints. Some 35 prisons had already funded posts from existing budgets, and HMPPS created a further 54 DSLs. A 2024 process review commissioned by HMPPS did not assess the impact of DSLs in depth, but noted that they were considered to be “valuable” by prison governors. As at January 2026, 17 Group Drug and Alcohol Leads (GDALs) were in post, currently funded for 12 months, to provide support across the estate, including establishments without dedicated DSLs.

3.26 Having a shared understanding of prison-level key metrics such as appointments which the patient did not attend or ‘under the influence’ instances can help staff at a prison identify problems affecting drug treatment and discuss solutions. Healthcare providers record missed appointments as ‘Did Not Attend’ (DNA). In 2024-25, nearly 160,000 of over 450,000 substance misuse appointments (35%) were coded DNA. Prisoners may not attend appointments for a variety of reasons, including refusal to participate in treatment, scheduling conflicts, or lack of enablement, but failure to attend has the potential for negative impacts on people’s health and wellbeing, the efficient use of health and prison staff resources, and the prison regime. Some providers report separately the causes of DNAs, but this varies by region, and NHSE does not collect or analyse DNA data because it considers it to be unreliable. NHSE has expressed concerns that data on ‘under the influence’ instances are not always readily available to them, preventing them from using these data to inform resource allocation and planning.

15 HMP Manchester is a listed building, which places stringent legal constraints on work that can be carried out, particularly to the exterior of the building.

16 Rule 39 mail is confidential correspondence between prisoners and individuals or organisations such as the Court, Bar Council or the prisoner’s Legal Adviser, which may only be opened, stopped or read in specific circumstances.

Appendix One

Our audit approach

Our scope

1 Our independent conclusions on the government’s approach to tackling the harms from drugs in prisons were reached by analysing evidence collected between July 2025 and January 2026. We formed our conclusions after considering the extent to which the Ministry of Justice (MoJ) and Department of Health and Social Care (DHSC) and others:

have clearly articulated their objectives and responsibilities for reducing harm in prison from illicit drug use;

have current policy and practice that is effective at reducing harm in prison from illicit drug use; and

provide services to tackle illicit drug use in prison that are resilient.

2 The report focuses on action taken to tackle drugs within the prison environment in England and Wales, not in the wider community. We cover the actions taken by HM Prison and Probation Service (HMPPS), MoJ, DHSC and NHS England (NHSE) within the prison environment to tackle the issues caused by drugs. We do not cover any related work that takes place before or after custody, or work that is undertaken by supporting bodies, such as the police. Healthcare in Wales is a devolved function, provided by NHS Wales, and is not covered by this report. We have not audited the clinical quality of healthcare services provided nor the sentences prisoners are serving.

3 Throughout this report we focus on the use of illicit drugs in prison (referred to as ‘drugs’ unless otherwise stated). We do not focus on the misuse of alcohol, which commonly occurs covertly within prisons, or the diversion of prescription medicines. However, both types of substance are generally included in the wider term ‘substance misuse’ that is sometimes used by health services.

Our evidence base

Interviews

4 We interviewed, both online and face to face, officials from MoJ, HMPPS, DHSC and NHSE, including teams responsible for:

policy and governance;

security and infrastructure;

drug testing methods;

budgeting and financial reporting;

data and insights, including data systems, dashboards and performance indicators;

pilots and evaluation;

regional and local operations, including NHS regions; and

commissioning and provider management.

5 We also interviewed wider stakeholders, including the following: Dame Carol Black, Forward Trust, HM Inspectorate of Prisons, Joint Combatting Drugs Unit, Prison Governors’ Association, and Prison Reform Trust. These interviews covered drug testing, security, commissioning, drivers of drug misuse, drug treatment, and challenges faced within prisons. We selected stakeholders with good knowledge of the prison system in England and Wales and drugs treatment. We identified stakeholders via desk research and our regular liaison points and invited these stakeholders by email to participate in an interview.

Document review

6 We reviewed MoJ, HMPPS, DHSC and NHSE documents for information to answer our main questions. We reviewed these documents to establish facts, including an understanding of drug prevalence in prisons, financing of drug treatment works, commissioning structures, governance arrangements and pilots and initiatives to tackle drug impacts demand. The main types of documents we reviewed were related to:

strategy and governance arrangements for bodies within the MoJ group and DHSC/NHSE;

drug prevalence monitoring and reporting, including governance board minutes;

data systems, including dashboards set up to monitor drug testing and drug treatment provision;

financial analysis and business cases of drug-related spend; and

initiatives to improve the testing and treatment of drug needs.

7 We also reviewed wider literature for context and information about our questions. This included:

previous reports by the National Audit Office; and

reports published or data shared with us by stakeholders; for example, Audit Wales, Care Quality Commission, Dame Carol Black, Government Internal Audit Agency (GIAA), Health Service Safety Investigations Body, HM Inspectorate of Prisons (HMIP), Independent Monitoring Boards, and Justice Select Committee.

Quantitative analysis

8 We analysed financial data, published statistics and data contained in the management information produced by MoJ, HMPPS, DHSC and NHSE, covering the period up to December 2025. We have not audited the accuracy or completeness of the data used. The datasets we analysed included, but were not limited to:

HMPPS prison population monthly bulletin, April 2025;

HMPPS Annual Digest, 2017-18 to 2024-25;

under the influence, multiple intoxications and naloxone use data management information, 2025;

National Drug Treatment Monitoring System, adults in prison in treatment, July 2018 to June 2025;

Alcohol and drug treatment in secure settings analysis, 2016 to 2024; and

HMIP Prisoner Survey Responses, 2021-22 to 2024-25.

9 With support from our Analysis Hub, we analysed prison inspection reports published since January 2023 to understand the number of prisons where substance abuse was raised as a priority concern by HMIP. The analysis covered inspections of prisons and combined prison/young offender institutions, representing approximately 76% of all prisons in England and Wales as of September 2025. Our approach used a sentence transformer model, all-mpnet-base-v2 (a type of deep learning model) to convert priority concerns and several phrases about drug misuse and substance abuse into numeric vectors that capture their meaning. We then calculated a similarity score between each priority concern and each of the phrases, using a well-established metric (cosine similarity). The highest similarity score among the phrases was used to determine whether a priority concern related to substance abuse. Following guidelines from the field of text analysis and to ensure that relevant priority concerns were not omitted, we initially considered pairs with a similarity score above 0.45. To ensure accuracy, we manually reviewed output from the model, removing any priority concerns incorrectly classified as referring to substance misuse. We aggregated the results and counted the number of prison inspection reports with a priority concern about substance misuse to assess the prevalence of the issue. As we used the term ‘substance abuse’, this may include diversion or misuse of prescription medication as well as illicit drugs.

Prison visits

10 We visited five prisons.

HMP Hull on 21 August 2025.

HMP Parc on 26 August 2025.

HMP Ranby on 27 August 2025.

HMP Nottingham on 28 August 2025.

HMP Downview on 6 October 2025.

11 We selected the prisons to give examples of the main contexts in which HMPPS and NHSE are tackling drug misuse and harms. This included the level of drug finds, the type and category of prisons, and prisons that were identified as examples of good practice or facing particular challenges.

12 Each of our visits included the following: an interview with the governor; interviews with key operational staff; and interviews with healthcare staff. We also spoke to security staff, Incentivised Substance Free Living wing staff, education staff and drug strategy leads, and substance misuse treatment sub-contractors.

13 The purpose of the site visits was to provide context on the prison environment, challenges faced by HMPPS in combatting drugs ingress and fostering recovery among prisoners, and how healthcare is typically delivered within prisons.

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