Police-led diversion for drug crimes.
Police-initiated diversion for drug-involved offenders
Police-led drug diversion is an intervention the police can initiate when they have contact with someone who is in possession of a controlled drug for personal use, or has committed another eligible offence and had some prior involvement with drugs.
Diversion aims to reduce reoffending and wider harms by approaching substance use as a health issue rather than a criminal justice issue. The intervention involves the police diverting suspects away from formal criminal justice processes – such as caution or prosecution – towards non-criminal justice alternatives, usually drug awareness courses or individualised support.
The police can refer people pre-arrest using out-of-court disposals or post-arrest while in police custody.
Effectiveness of police-initiated diversion
Adult and young offenders
Many studies have evaluated the impact of police schemes designed to divert offenders who had committed a wider range of eligible crimes other than drugs offences, and who may not have had any prior involvement in drugs.
The evidence on the effectiveness of diversion for low-risk young people is positive. A meta-analytic review, pooling the results of 19 studies, showed youth diversion had reduced subsequent offending overall. It found that, if the reoffending rate for young people processed in the usual way was 50%, the rate for young people who were diverted was 44% – a reduction of 6 percentage points.
The evidence on the effectiveness of adult diversion is less clear-cut but promising. A systematic review of 47 studies found eight studies that looked at re-arrest rates among adults who had been diverted, compared to rates for adults treated as usual. Four of these studies showed diversion had significantly reduced reoffending. Three provided evidence of diversion having had no positive or negative impact, and one found higher re-arrest rates among diverted adults.
Drugs-involved offenders
A meta-analytical review pooling the results of 16 studies showed that overall, drug diversion had resulted in a small but significant reduction in drug use among offenders (Hayhurst and others 2017). The results on reoffending could not be pooled for methodological reasons, but individual studies pointed to diversion having resulted in small, significant reductions in reoffending.
A second scoping review based on 31 studies reached similar conclusions. It found limited but promising evidence that drug diversion had reduced drug use and reoffending (Lindquist-Grantz and others 2021).
An international realist review (Stevens and others 2022) looked at the contexts and mechanisms as well as the outcomes of drug diversion schemes and showed they can work by providing access to more positive support and reducing the costs and harms of criminal justice sanctions.
College supported evaluation of police-initiated pre-arrest drug diversion
The College is working with a partnership led by Professor Alex Stevens from the University of Kent on an impact, process and economic evaluation of pre-arrest drug diversion for adult offenders. The study aims to show whether and how drug diversion works, for whom, when and why.
The project concludes in spring 2025 and findings from the three-year evaluation will be published when they are available.
The evaluation is made up of the following elements.
Diversion scheme manuals
Workshops were carried out with more than 70 participants to develop detailed descriptions of the schemes in Durham, Thames Valley and the West Midlands. A theory of change setting out how, hypothetically, drug diversion could bring about improved outcomes was also developed.
Read the scheme manuals for Durham, Thames Valley and the West Midlands, and the theory of change in the National Police Library.
Process evaluation
Interviews with 225 police officers, service providers and drug-involved offenders, six focus groups and analysis of police data is being carried out to understand how closely diversion in Durham, Thames Valley and the West Midlands follows the scheme manuals. The research looks at whether the theory of change holds in practice, and what is likely to be need for diversion to be effective.
Impact evaluation
Quantitative analysis is being carried out to assess the impact diversion has had on crime and health outcomes across 20 police forces. The assessment involves comparing rates of reoffending, hospital admissions and entry into drug treatment for offenders in places with drug diversion schemes with those for offenders in places without schemes.
Economic evaluation
Analysis will be carried to weigh-up the cost of diversion against the financial value of any benefits it has delivered. The economic evaluation also aims to identify where any costs and benefits fall across policing and health systems.
Equity assessment
Data from Durham, Thames Valley and the West Midlands is to be examined to understand whether the use and impact of drug diversion varies according to the protected characteristics of offenders.
EMMIE framework summary
The project will conclude by combining and summarising findings on the Effects, Mechanisms, Moderators, Implementation and Economics (EMMIE) of police drug diversion schemes.
Read more about the evaluation on the Research Projects Map and in this open access evaluation protocol.
The evaluation is being delivered in partnership with:
- Bradford Institute of Health Research
- Office for Health Improvements and Disparities in the Department of Health and Social Care
- Loughborough University
- Open University
- University of Sheffield
- University of York
- User Voice (a service user-led charity)
- National Police Chiefs’ Council
The partnership is receiving £1.9m from the Evaluation Task Force in the Cabinet Office and Treasury.
Example of relevant practice
Project Divert (West Midlands Police and Office of Police and Crime Commissioner)
An officer can offer a community resolution as an alternative to prosecution to almost anyone found in possession of a controlled drug for personal use.
If the person agrees to engage with a drug intervention, the officer refers them to a commissioned service provider and resolves the crime without the person being taken to court or getting a criminal record.
The drug intervention starts with the person having a one-to-one telephone assessment with a substance misuse worker. During the session, the substance misuse worker assesses potential health risks to the person and provides personalised advice on how to keep safe.
The substance misuse worker also refers the person to the most appropriate intervention course. Most people attend a two or three hour online educational course. The course consists of interactive group exercises designed to educate participants about the personal impact of drugs, such as on their own health, relationships, and work; as well as the wider impact of drugs, such as exploitation and modern-day slavery.
People who do not attend the course do not receive a penalty but are prevented from being offered the course again. Officers can offer diversion repeatedly to people found in possession of drugs even if they have already completed a course, so long as they engage in the process every single time.