Flowers are left at the scene following the death of Amaan Shakoor who was shot on Monday night in WalthamstowCredit: PA
It's just endemic across most of London, particularly inner London. For some reason this isn't just defined to one or two little corners it just seems to have spread and the mindset has crept in across London.
It's around social deprivation. If you were to pull out a map which showed the most deprived boroughs I would guarantee there is a postcode war there.
– PATRICK GREEN, HEAD OF THE BEN KINSELLA TRUST
He said young people get stuck in such "a bubble" that he has met men in their mid-20s who have never left Tottenham, even to travel as far as Oxford Circus.
There are particular rivalries in Wood Green and Tottenham; Croydon and South Norwood, Newham and Stratford.
Social media has also been highlighted as fuelling a cycle of tit-for-tat violence.
Beth Murray from youth charity Catch 22 said violent videos can end up being shared with thousands of people, normalising horrific incidents like stabbings and heaping "shame" on the victim, pressuring them to retaliate.
Only a fraction of the violence the organisation deals with is gang-related, she said, with the majority being "kids with knives getting out of control with each other".
Police estimate that in London half of gun crime is linked to gangs and around a fifth of knife crime.
Most of the shootings and stabbings that we see often aren't linked to organised crime or gangs, they are kids with knives getting out of control with each other. What we're seeing is that somebody might get stabbed, that might get filmed, that might go on Snapchat, that might be shown to hundreds of people who might then see that as normal, they might share that, that might then go out to thousands of people. That does two things. That desensitises young people to what's going on around them and secondly it creates a momentum behind it. Somebody who has been stabbed will then have to retaliate because they've been shamed, or their friends will feel as though they have to retaliate because they feel they've been publicly shamed. It creates a cycle of violence which previously didn't exist, we'd see a lot more isolated incidents. Now we see a lot more people who are using social media to act as a catalyst for youth violence.