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Increasing public confidence through improved transparency in policing.
Increasing public confidence through improved transparency in policing
Supporting the criminal justice process
Supporting the criminal justice process
Improving the investigation of complaints
Improving the investigation of complaints
Increasing the potential for evidence based prosecutions to support vulnerable victims
Increasing the potential for evidence based prosecutions to support vulnerable victims
Making stop and search more accountable to communities
Making stop and search more accountable to communities
Smarter, more transparent policing
Smarter, more transparent policing

MPS trial of BWV

In May 2014 the MPS in collaboration with the Mayor’s Office for Policing And Crime (MOPAC) and the College of Policing began a 12 month trial testing the impact of Body Worn Video (BWV) on; complaints against the police, frequency of stop and search and criminal justice outcomes for violent incidents.

The trial, thought to be the largest in the world, took place across ten London boroughs;

  • Camden
  • Hillingdon
  • Ealing
  • Barnet
  • Lewisham
  • Croydon
  • Bexley
  • Bromley
  • Havering
  • Brent

The trial boroughs were selected on the basis of their complaint, crime and stop and search rates. The trial was only focused on Emergency Response Teams (ERTs).

The trial was run as a ‘randomised controlled trial’ where the five ERTs were randomly assigned to either the treatment group, who wore BWV cameras (two teams), or the control group (three teams). 814 officers in 19 teams, were assigned to wear cameras and 1,246 in 29 teams didn't receive cameras.

On the completion of the trial the evaluation compared the ‘treatment’ and ‘control’ groups in terms of;

  • The proportion of incidents attended that resulted in a criminal justice outcome.
  • Stop and search practices.
  • Complaint rates.
  • Officers’ attitudes and self-reported behaviour.

During the trial BWV captured 48,281 recordings.

Key Findings

Overall the findings suggested there were potential benefits of BWV, although those related to criminal justice outcomes were not fully realised during the timescales of the trial and required the support of criminal justice partners to be achieved.
The general findings were:

  1. BWV can reduce the number of allegations against officers, particularly of oppressive behaviour. Complaints related to interactions with the public also reduced and, although it did not reach statistical significance, the trend in overall complaints was consistent with these findings.
  2. There was no overall impact of BWV on the number or type of stop and searches conducted. In addition, there were no differences in officers' self-reported behaviour relating to how they conducted stops.
  3. No effect was found on the proportion of arrests for violent crime. When an arrest had occurred, there was a slightly, lower proportion of charges by officers in a BWV team.
  4. There was no evidence that BWV changed the way police officers dealt with victims or suspects.
  5. The Public Attitude Survey found in general, London residents are supportive of BWV with their opinions of the technology positively associated with their views of how 'procedurally just' the police are, and their confidence in the MPS.
  6. Officers reported a range of innovative uses of BWV, including professional development; use of intelligence and sharing information with partners.

CoP report

The College of Policing’s full report, ‘Police, Camera, Evidence: London’s cluster randomised controlled trial of Body Worn Video’ is available through the web-link below:

Prior to and during the trial of BWV, the MPS consulted extensively with the public, including the MPS Stop and Search Forum, various IAGs, the NHS, Big Brother Watch, Liberty and Brixton Community Meeting. BWV policy has been informed by the College of Policing guidance 2014, Information Commissioner's code of practice for the use of CCTV systems in public places 2013 (, Information Commissioner's guidance for the police, criminal justice and border sector. (, Office of the Surveillance Commissioner - advice and guidance notes ( and the Surveillance Camera Commissioner CCTV codes of practice.

Public attitude surveys have been conducted on MPS use of BWV, confirming public support of use of BWV in London.