Gangs Violence Matrix

Gangs Violence Matrix (GVM, or Gangs Matrix) was a controversial system detailing thousands of alleged street gang members in London, UK.

Established in 2012 in the wake of the 2011 London riots as a watchlist of people designated by police as “gang nominals”, the GVM was developed and operated by London's Metropolitan Police Service ('Met Police').

The system used one or more algorithms to rank and categorise people included on the database, based on the risk each 'gang member' posed to others, and the extent to which the police and partner agencies interacted with that person. 

The GVM was subject to multiple investigations, research studies, and legal reviews by Amnesty, Liberty, StopWatch and other rights organisations.

The MPS scrapped the Gangs Matrix in February 2024, replacing 🔗 it with an adapted "violence harm assessment" (VHA) approach, which the Met described as more "precision-led".

Risks and harms 🛑

The Gangs Violence Matrix was criticised for being inaccurate, unfair, and discriminatory, as well as for exhibiting poor transparency and accountability. 

Transparency and accountability 🙈

The Gangs Violence Matrix is seen to suffer from multiple transparency and accountability limitations, including: 

• Decision-making processes. Details of the matrix and its operation were not fully disclosed to the public.

• Scoring system. The criteria and algorithms used to score and categorise individuals were not transparent.

• Data sharing. Questions surround how information from the matrix was nshared with other agencies.

• Independent oversight. There was insufficient external review of the matrix's implementation and impacts.

• Complaints and appeals process. Individuals struggled to know if they were on the matrix or how to contest their inclusion.

• Impact assessments. There was limited public information on how the matrix's effectiveness was evaluated.