[nomadking]

Apparently:-

It would be very similar to the system in Glasgow, formerly the knife crime capital of
Europe, where stab wounds have halved in 12 years.
It also mirrors the anti-terrorism Prevent strategy, set up in 2006, which is used to
identify youngsters at risk of being sucked into extremism.
Under the Glasgow model, gang members and those at risk of joining gangs are referred
to violence reduction units. There, they are offered mentoring by someone with similar
experiences of violence or given opportunities to further their education.

Although the difference in demographics might make it less likely to work in London.