Knife offenders are set to be tagged with GPS devices on release from prison as part of a new trial.
In a bid to reduce violence in the capital, 100 offenders across four London boroughs worst hit by knife crime will be fitted with the technology.
Those deemed most likely to reoffend will have their movements automatically checked against locations of reported crime and matches will be shared with police.
London mayor Sadiq Khan announced the pilot on Monday.
The boroughs of Lewisham, Lambeth, Croydon and Southwark will all take part.
Mr Khan said the causes of violent crime are "extremely complex", blaming poverty, inequality and the lack of opportunities exacerbated by "huge" government cuts.
"This innovative pilot will build on the good work of the City Hall-funded violent crime taskforce by helping offenders integrate back into society and reducing the risk of reoffending, as well as giving the police the information they need to thoroughly investigate reported crimes," he said.
Trackers will be fitted to offenders leaving prison for crimes such as knife possession, wounding and grievous bodily harm under the plan to be launched on February 18.
The announcement came after a man believed to be in his 30s was stabbed to death in East Dulwich, south-east London, shortly after 3am on Sunday.