There have been no convictions of British law enforcement officials implicated in the deaths of 509 ethnic minorities in custody since 1991, a UK-based think tank study published Monday said.

MOSCOW (Sputnik) – The Institute for Race Relation's (IRR) "Dying for Justice" report found that six out of seven people who died in "restraint deaths" were from ethnic minorities, over a quarter of those who died in police custody were from minority backgrounds, with 24 people dying in immigration-related detention. Among Britain's black population, the report says only one death led to the prosecution of a police officer, and only one bereaved family of a detainee who died in custody received compensation.

"Although inquest juries have delivered verdicts of unlawful killing in at least twelve cases, no one has been convicted for their part in these deaths over the two and a half decades," the report reads.

Compounding the problem, authors say, is a so-called joint enterprise law used by law enforcement officials as a "dragnet device" in convictions. Joint enterprise paves the way for murder convictions "even if the unlawful act occurs spontaneously and solely on the basis of an individual's presence at the scene" of the crime.

In contrast, pursuing legal action over the 509 deaths in custody is further complicated by self-defense, necessary action and legitimate purpose legal protections.

"As more deaths take place and no one is ever prosecuted, it inevitably sows seeds of incredulity, anger and despair," Harmit Athwal, the study's co-editor, said in a press statement.

According to a poll conducted by the United Kingdom's National Center for Social Research in 2013, up to one-third of Britons admitted to feelings of racial prejudice.