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Liaison and diversion schemes work

Longitudinal study finds that custody-based liaison and diversion schemes reduce reoffending and improve mental health.

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Eight year study in two police areas

A new longitudinal study into the impact of liaison and diversion (L&D) schemes in police custody has found promising results. The research: Are Liaison and Diversion interventions in policing delivering the planned impact: A longitudinal evaluation in two constabularies? by Eddie Kane, Emily Evans, Jurgen Mitsch & Tahseen Jilani used a pre–post service use design. 

NHS records in two counties were searched for evidence that patients had been involved with L&D services while in police custody during the period July 2009–December 2017.  January 2009–July 2014 was defined as the pre-intervention period and any time after contact as the post-intervention period. Data from the Police National Computer were gathered for each period for these individuals, to assess their pre-post L&D contact offending histories. NHS Trust data were similarly gathered to assess their pre-post use of mental health legislation. 4,462 individuals were identified who had used L&D services in police custody. 

Liaison and Diversion

Liaison and Diversion (L&D) services identify people who have mental health, substance misuse, learning disability or other developmental vulnerabilities when they first come into contact with the criminal justice system as suspects, defendants or offenders. The service can support people through the early stages of the criminal justice pathway, refer them for appropriate health or social care or enable them to be diverted away from the criminal justice system into a more appropriate setting, if required. The aim is to improve overall health outcomes, reduce further police contact and re-offending rates and avert disorder-related crises.

These NHS England (NHSE) funded schemes operate to a standard model and are now available in every part of the country. L&D sees teams of NHS staff located at police custody centres and courts in order to assess, divert or appropriately support individuals.


People who had contact with L&D services were found to have significantly reduced their reoffending, whatever the type of crime they committed. The group were also found to be significantly less likely to be subject to the four most common forms of compulsory treatment under mental health legislation:

  1. the police safety provision (s136),
  2. detention in hospital for assessment (s2),
  3. for treatment (s3) or
  4. retention in hospital when a voluntary patient wants to leave but is deemed to need further assessment (s5[2], s5[4]


It is clear from the study that an L&D intervention is co-related with beneficial change for individuals and
society more generally beyond simply providing support and advice to individual. The authors are not able to say definitively what aspects of the intervention had most impact and the reality is probably that it varied from individual to individual. The authors express the opinion that L&D intervention provided an opportunity for individuals to connect, or in many cases, reconnect with MH services for treatment or support. It is also possible that the added support provided by the L&D teams, especially the initial extended involvement of L&D Support Workers to help individuals attend and make the most of appointments with GPs, Community MH Teams, Housing and Benefits Offices, may have been an important factor. Previous research has also indicated that L&D is seen as providing expert support and advice from MH nurses co-located with the police and improves communication and knowledge and policing response between police and NHS staff enabling better decisions to be made more quickly.

A very significant investment has been made into L&D services across the Health and Criminal Justice Systems and this study points to what appear to be related positive impacts. The findings appear to confirm that investments in L&D are worthwhile from an individual’s point of view but also from an economic standpoint. The reduction in offending post-intervention is statistically significant for all of the frequent, volume crime types examined in the study.


Thanks to Frederick Tubiermont for permission to use his header image, previously published on Unsplash.

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