Move gang members from home turf, says review
11 March 2013 Last updated at 15:27 GMT
More than half of all London boroughs are affected by gang violence and it can can erupt when someone strays into the wrong area.
Now, a Home Office review has been looking at how best to deal with the problem.
BBC London's special correspondent Kurt Barling reports on one project, which moves gang members away from their home turf voluntarily to help keep them away from trouble.