Behind many recent murders in London are young men who are traumatised and excluded

On the afternoon of 18 April 2016, a Monday, Lewis Elwin was dropped off by a relative in Moyser Road, a residential street in Tooting, south London.

The 20-year-old’s mother and five older siblings were worried about him: they feared he was mixing with the wrong crowd, and doing so at a time when tit-for-tat violence among youth gangs was costing lives.

But this was considered a safe area: a tree-lined street of Edwardian family homes, coffee shops and a flower shop. Elwin called a friend and they arranged to meet.

He walked 200 yards to the south: by the time he turned left into Penwortham Road he had broken into a jog. By this time, police nowbelieve, Elwin had already sustained the knife wound that had pierced his chest. He collapsed, and died within minutes.

On the first anniversary of Elwin’s death, his friends gathered at his graveside, where they danced and sang. Some wore T-shirts bearing his picture beneath the message “RIP Lewis”.

Also present was a young film-maker who filmed and recorded the group. Using a camera on a drone, he also shot footage high above the 14-storey tower blocks of a housing estate in Tooting where some of the young men lived.

Some can’t even cross the road without putting themselves into a dangerous location Ebony Reid, sociologist

The film was edited and handed over to Elwin’s friends, who posted it on YouTube on 21 April 2017. Now, thousands of people could see that a