The BBC film sees Elba meet prime minister Sir Keir Starmer, who said that his party would commit to halving knife crime if elected, and the King, where the pair discussed solutions to the problem with some of the young people most affected by youth violence.

In the documentary, called Idris Elba: Our Knife Crime Crisis, the Hollywood star meets a 17-year-old boy at Feltham young offender institution who first began carrying a blade when he was 13. He grew up in a violent home and had been badly bullied at school for having dandruff.

Jim Webster, who was Plymouth's police Commander between 2007 and 2009, oversaw a number of high profile investigations including nursery paedophile Vanessa George and Exeter bomber Nicky Reilly. During his reign he suggested that one way to reduce the number of victims of stabbings was a fundamental but simple redesign of kitchen knives.

Luther star speaks ahead of the release of BBC documentary in which actor talks to victims’ families, police officers and teenage offenders

Banning the sale of zombie knives is a positive step, but schools need to intervene earlier to help tackle the UK's knife crime crisis, says Idris Elba. The actor, 52, has spent the last year making a documentary for the BBC about solutions to knife crime,