Sephton Henry was once one of south London's most notorious gang members. He started selling drugs at the age of eight, and had been to prison seven times by the time he was 23.

He realised his life was spiralling out of control and decided to make a change. Sephton now works with charity Gangsline, which helps young people and community staff to tackle gang culture.

Producer: Aaron Akinyemi

Video journalist: Cebolakhe Luthuli