What is the gangs violence matrix?

The gangs violence matrix (GVM) is an intelligence tool we use to identify and risk-assess gang members across London who are involved in gang violence. It also seeks to identify those at risk of victimisation.

The aim of the matrix is to reduce gang-related violence, safeguard those exploited by gangs and prevent young lives being lost. The matrix is not an intelligence tool for serious and organised crime, its focus is on violence. 

How does the matrix work?

The GVM measures the harm 'gang nominals’ (people who are named on the matrix) pose by scoring them based on evidence of them committing violence and weapons offences, any police intelligence relating to them having access to weapons, or them being involved in, or at risk from, gang violence.

From these scores every individual is graded as Red, Amber or Green (RAG rating) denoting the level of risk (victim) or harm (offenders) they present. This rating enables us to identify the most violent or at risk gang members and work with partners to prioritise how we respond.

The GVM also identifies gang members who have been repeat victims of violence and need support to safeguard them from being further victims and to divert them away from gangs. 

Some of the key benefits of the GVM are that it:

  • identifies gang members in London and prioritises the current most violent gang subjects
  • identifies gang members who have been victims of violence and are at risk of becoming further victims of violence
  • aids the prioritising of resource allocation and methods of intervention
  • highlights possible gaps in activity or intelligence on violent gang subjects

Every locally based Basic Command Unit (BCU) in the Met has their own matrix. These are combined to produce a single matrix across London to provide an assessment of the risk gang nominals pose. All locally based BCUs also share data with their partners to enable a multi-agency approach to tackling gangs in London.

How are names added to the matrix?

When assessing whether someone should be included on the matrix the threshold is: ‘Someone who has been identified as being a member of a gang and this is corroborated by reliable intelligence from more than one source (eg, police, partner agencies or community intelligence).’

They will only be added to the matrix if they fit this definition.

A ‘gang’ is defined as a: ‘relatively durable, predominantly street-based group of young people who:

(1) See themselves (and are seen by others) as a discernible group, and
(2) Engage in a range of criminal activity and violence.

They may also have any or all of the following features:

  • identify with or lay claim over territory
  • have some form of identifying structure feature
  • are in conflict with other, similar gangs’

This definition is distinct from – and should not be confused with – other criminal structures, such as organised crime networks, which merit a different policing approach.

Who can access the gangs violence matrix and what training do they have?

Only officers and staff that have been trained in using the matrix are able to access it.

This training is separated into three categories:

  • BCU leads and their deputies who are responsible for the matrix
  • officers and staff who edit (add and remove) subjects from the matrix
  • awareness training for other officers and staff who may access the matrix but are not able to edit it

All editors are required to have completed a data protection training course and have been authorised by their BCU lead to have editing access.

How many names are on the matrix?

The number of individuals on the GVM changes daily. We publish figures every quarter and the latest figures are available in the documents below.

How do you get off the matrix?

Individuals’ names are removed on a regular basis, over 4,000 have been removed from the GVM since its inception in 2012.

Here are some examples of why individuals’ names are removed from the matrix.

  • There is evidence they have exited gang lifestyle.
  • They are engaging in a diversion program for a period of time (6 months) and haven’t come to police notice since that engagement started.
  • They have not come to police notice for a significant period (12 months).
  • They have moved away from London and are no longer believed involved in gang criminality within the Metropolitan Police Area.

Who uses the matrix?

The GVM is used in the Met by a number of police officers and staff in roles with a relevance to gangs.

Information from the matrix is shared with partners to make sure there’s a multi-agency approach to tackling gangs.

We work with community safety partners (CSPs) and third-party organisations to make sure individuals involved in gangs who need help or want assistance to leave gangs receive the support they need.

This can include mentor schemes, help with education, employment, re-housing and more. Local partnership meetings take place at a borough level where gang nominals and others are discussed to achieve these ends.

Statutory partners will differ in each London borough/BCU but will include CSPs such as the local authority, Youth Offending Service, National Probation Service, Community Rehabilitation Company, health, education and more.

Under the Crime and Disorder Act 1998 we have a responsibility, working with CSPs, to formulate and implement strategies for reducing crime, disorder and reoffending, and we will share information with CSPs to facilitate such strategies.

Partners are selected based on being able to provide relevant information about individuals that can help in positive interventions to move them away from gangs and criminality.

Where the gangs violence matrix is shared with partners this is with a Data Sharing Agreement in place.

Information Commissioner’s office enforcement notice

An enforcement notice was served on the Metropolitan Police Service by the Information Commissioner’s Office (ICO) in November 2018, following its review of the GVM. 

This notice relates to the contravention of data protection principles (Data Protection Act 1998). We are obliged to comply with the findings.

We assert that the rationale to continue to use and to operate the GVM is compliant with the Human Rights Act and it is monitored to ensure that it is used proportionately and fairly to reduce serious crime in London.  

The GVM has assisted in preventing many gang members from committing, or being the victims of, serious violent crimes, so we view this as a very effective intelligence tool to direct our activity.

This can be evidenced from analysis completed for the recently published Gang Matrix Review by the Mayor’s Office for Policing and Crime (MOPAC).

When looking at a cohort of 7,000 individuals who had been on the GVM for five years, the cohort presents an increasing proportion of ‘sanctions’ (offences for which the individual received a conviction, caution or warning) before being added to the GVM, a sharp decline once on the GVM and then a more gradual decline once removed from the GVM.

The same pattern can be seen when looking at sanctions for violent offences only.

Victimisation follows a similar pattern to offending with sustained reduced levels both while on the GVM and more significantly after being removed from the GVM. From this we can infer the GVM is key in reducing risk among those included on it. This saves lives. 

Over the last 15 months, there has been significant external scrutiny of the GVM.

As well as the ICO review, Amnesty International have raised concerns about the use of the GVM and the MOPAC review of the GVM was published in December 2018.

We are now implementing a number of measures to make sure that we can comply with the requirements of the enforcement notice and the MOPAC review.

On this page, we’ll show the progress we’re making with the improvements required.

Download the Information Commissioner's Office Enforcement Notice and the MOPAC review below.

The Data protection impact assessment and Equality impact assessment are currently under review but the previous versions remain available below.

The PDF(s) on this page may not be suitable for users of assistive technology. We are in the process of updating them, but please email us to request an accessible version. See our accessibility statement.