Mr Briggs died while in police custody on the 4th of November 2013, after he was detained under section 136 of the Mental Health Act. The 39-year-old had come to the attention of Bedfordshire Police after a member of the public called 999 concerned for his welfare due to his reported erratic and confused behaviour.

Attending officers restrained the father of two in a prone (face down) position for over 13 minutes, while staff from the East of England Ambulance Service watched on and did not assess or communicate with Leon. He was then transported to Luton Police Station; unable to walk he was carried to a cell where he was restrained again and then left unconscious for 6 minutes.

Under two hours after being detained in a cell, Mr Briggs was pronounced dead at hospital.

In an inquest, the primary cause of his death was determined to be “amphetamine intoxication with prone restraint and prolonged struggling”, and a secondary cause of an underlying heart condition.

Sgt Grant Waterman apologised at the inquest in February for remarking in his evidence that Mr Briggs had staged a “dirty protest” as he lay motionless on the floor of the police cell, saying that he had noticed that Mr Briggs had urinated himself, but he believed it was “intentional” – despite the inquest hearing that police training treats urination as a warning sign for loss of consciousness.

Mr Briggs was treated as “a threat” rather than as someone “in need of help”

The jury concluded last week that Bedfordshire Police’s inadequate welfare assessments, and their inappropriate use of force all contributed significantly to Leon’s death.

Responding to the verdict Sophie Corlett, director of external relations at Mind, commented that Mr Briggs death highlights not only the “humiliating and dehumanising” use of restraints for people experiencing a mental health crisis, but also the role of institutional racism in the treatment of Black men by the police.

Mr Briggs had a bi-racial heritage, and was logged by the police control room as 'an aggressive male'.

Sophie Corlett added: “Leon Briggs is another person in a long line of Black men who have died at the hands of those meant to keep them safe. His death, along with those of Olaseni (‘Seni’) Lewis, Kevin Clarke and many more, should have never happened… Too often, rather than being seen as someone who needed help, Black men are seen as a threat, treated that way, and end up dead.”

“Some communities - particularly Black men - are far more likely to be held against their will under the Mental Health Act, often subjected to humiliating and life-threatening practices like physical and chemical restraint. The increase in detentions demonstrates that the Act, and wider mental health care, fails to support people when they are acutely unwell, especially people from different Black Asian and other ethnic minority communities.”

Margaret Briggs, Leon's mother, said of the verdict: “Today marks a milestone in our fight for justice for Leon. After seven long years of waiting, those present during Leon's restraint have finally been made to explain their actions… We think that Leon’s race was a factor in the way he was treated by the police. He was treated as someone who posed a threat rather than someone in need of help.”

Bedfordshire Police released a statement apologising to Leon’s family, and deputy chief constable Trevor Rodenhurst said in a video statement: “The family and friends of Leon Briggs have had to wait far too long to hear all the facts surrounding his death and our thoughts are of course with them at this very difficult time… The attending officers chose to restrain him so he could be taken to a police custody suite where he could be assessed.”

“We’ve made extensive changes since 2013 but we remain absolutely committed to working with the coroner and all of our partners in order to identify and make any necessary further improvements.”

Other recent deaths involving police restraints or misconduct and mental ill-health include Moyied Bashir, Brian Ringrose, Kevin Clarke, Darren Cumberbatch, Douglas Oak, Mzee Mohammed-Daley, Sean Rigg, Thomas Orchard, Kingsley Burrell, and Seni Lewis.