Joint case building by the police and Crown Prosecution Service: final report
Rt Hon Yvette Cooper MP
Home Secretary
Home Office
2 Marsham Street
London
SW1P 4DF
2nd September 2025
Joint case building by the police and Crown Prosecution Service: final report
I am writing to you in response to the joint inspection report by His Majesty’s Inspectorate of Constabulary and Fire and Rescue Services (HMICFRS) and His Majesty’s Crown Proseuction Service Inspectorate (HMCPSI) on joint case building by the Police and Crown Prosecution Service (CPS).
The report found that despite earlier efforts, there remain persistent barriers to effective collaboration. Communication between agencies is often inconsistent, roles and responsibilities are not always clear, and processes can be complex. These factors combine to weaken case building and ultimately undermine outcomes for victims.
It recognised that whilst senior leaders in both organisations have committed to working better together, this has not yet translated to improvements consistently experienced by frontline officers, prosecutors or victims.
This inspection report makes 18 recommendations in total with 3 directly for Chief Constables.
I welcome the inspection findings and the recognition it gives to challenges faced by both the police and prosecutors when building cases. I agree with the findings that inefficiencies and delays can have a significant impact on victims.
As Police and Crime Commissioner and Chair of the Local Criminal Justice Board (LCJB) in West Mercia, improving quality across the criminal justice system continues to be a priority, with victims remaining central to these efforts.
Through the West Mercia LCJB, I regularly monitor and discuss data relating to file quality with partners across the criminal justice system. This has led to improved collaboration between the force and the CPS to improve the quality of investigations. As
a result, fewer cases require rework, or additional action plans allowing officers to focus on progressing cases more efficiently.
I have recently been updated on force and CPS activity following the publication of this report, with a joint action plan being explored to address key recommendations. One element of this includes the scoping of an innovative approach for a Large Language Model (LLM) Artificial Intelligence (AI) resolution to file build. Professor’s Kirschmaier and Wang are leading on this initiative, embarking on random control trials seeking to optimise the Police-CPS interface using two competitive LLMs. They are currently trialling in West Midlands and Greater Manchester Police and are seeking a regional force to support the trial.
Through this proposed trial the aim is to optimise the interface by automating a quality control process, and in a second step make predictions about the likelihood of success in court by organising two opposing Large Language Models (LLMs); one for the police, and the other for the CPS.
Whilst this is a positive development, it is clear that broader systematic improvements will require additional investment. Sustained enhancement of case building depends on resourcing areas such as technology, training and staffing across both the police and CPS. This need is particularly urgent given the ongoing court backlogs which lengthen the time victims must then wait for their cases to be heard.
Without this adequate investment from central government, progress achieved locally risks being undermined by delays elsewhere in the system. As Commissioner, I will continue to monitor these developments closely and advocate for the resources necessary to support both innovation and effective case progression.
John Campion
Police and Crime Commissioner
West Mercia