An independent review of the treatment of Black, Asian, and Minority Ethnic (BAME) individuals in the UK criminal justice system concluded that the London police's Gangs Violence Matrix was inaccurate and discriminatory.

The Lammy Review, commissioned by then UK Prime minister David Cameron of England and Wales' criminal justice system and conducted by David Lammy MP in 2017, examined the treatment of Black, Asian, and Minority Ethnic (BAME) individuals in the criminal justice system.

It also took a critical look at the Metropolitan Police Service's Gangs Matrix, concluding that there was a disproportionate focus on black and ethnic minority individuals in the matrix, supported by data showing that approximately 80 percent of individuals on the Matrix identified as black.

The review also found that 64 percent of those on the GVM were classified as low risk (or green), raising questions about the necessity and proportionality of their inclusion, and noted that it included over 100 children under the age of 16, highlighting concerns about the criminalisation of young people.

Lammy called for a comprehensive overhaul of the Gangs Matrix operating model, including establishing clear criteria be established for inclusion on the database, improved transparency and accountability, including informing people if they are listed on the database and clear mechanisms for challenging inclusion.