London’s Metropolitan Police force has been accused of racial discrimination over its use of a “gangs database” that an advocacy group has claimed breaches human rights.

Amnesty International said Wednesday that the Met’s “Gang Violence Matrix,” a database holding information of approximately 3,800 people, listed a disproportionate amount of minorities.

Seventy-eight percent of those listed were black, compared to 27 percent of serious youth offenders in London identified as black British.

The database was introduced in 2011 after a series of riots across the U.K. that centred in the capital. Its contents list past criminal records, social media accounts and personal information used to identify so-called gang members.

The police database even lists the type of music and videos watched online. Those listed are given a “violence ranking” in green, amber or red.

Amnesty said that the “deeply flawed” database, frequently shared with local governing bodies, violated young people’s privacy rights.

The human rights watchdog said police had been known to use fake online profiles to “covertly befriend” people in a bid to monitor what they did online.

“It is clear that many people are being profiled based on factors that have nothing to do with serious offending, but rather on indicators of youth culture. This is nothing less than a reckless and counter-productive approach to policing,” the report said.

Speaking to the BBC, community campaigner Stafford Scott said that he had found that in the north London borough of Haringey, 99 out of 100 people listed were young black men.

“Some young people identified as part of a gang may not yet have been drawn into gang violence,” the Metropolitan Police 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.”

It added that the type of music someone listens to “has no bearing on whether someone is placed on the matrix… However, evidence that someone is glorifying gang violence in a music video posted on social media can be used as an intelligence source.”