Amnesty said the Metropolitan Police Gangs Matrix is "stigmatizing young black men for the type of music they listen to or their social media behavior." The database holds information on almost 4,000 people. The vast majority are teens or young men, and 78 percent are black. Police figures show 27 percent of those prosecuted for youth violence are black.
Set up after England's 2011 riots, the database compiles information including police records, information from local authorities and social-media entries to identify suspected gang members. It then uses a secret algorithm to calculate "risk of harm" scores based on the likelihood an individual will be involved in violence.
Forty percent of people on the database have a harm score of zero, meaning there is no information linking them to violence in the last two years. Gang rivalries have been cited as a factor behind a rise in stabbings in London, and some community workers have suggested social media has helped disputes escalate quickly to violence.
"There is clearly a huge problem with knife crime violence at the moment in London, but the Gangs Matrix is not the answer," said Amnesty U.K. director Kate Allen. "It's part of an unhelpful and racialized focus on the concept of gangs."
Amnesty also said in a report that there were no clear processes for reviewing or updating the database, or for challenging the inclusion of a name. The Information Commissioner's Office said it was "considering how the database is used and if any aspects of it constitute a breach of the Data Protection Act."
Scotland Yard defended the database, saying it aimed to "reduce gang-related violence and prevent young lives being lost" by steering young people away from gangs. "Some young people identified as part of a gang may not yet have been drawn into gang violence," the force said in a statement. "These individuals will be offered support to divert them away from activity that may result in either violent offending or them becoming a victim."