Why would you stab someone?

After two 17-year-olds were killed in separate incidents in London and Greater Manchester at the weekend, we hear from a former gang member who tells our Home Affairs correspondent Danny Shaw why he’d never leave the house without carrying a knife. We also hear from BBC London reporter Greg Mckenzie who has covered 19 murders in the capital already this year. Producers: Philly Beaumont and Duncan Barber. Editor: John Shields. Mixed by Nico Raufast.