Scotland Yard is to nearly double its resources for fighting gang crime in a renewed crackdown on the problem.
The force has vowed to take a more joined-up approach to tackling gang crime in the capital.
Today hundreds of Metropolitan Police officers conducted a series of raids on properties in a bid to track down and arrest suspected gang members believed to be involved in crimes including assault, robbery and drugs supply.
At a press conference at New Scotland Yard, Assistant Commissioner Mark Rowley said that as of mid-morning, 109 warrants had been made resulting in 121 arrests for offences including the supply and possession of drugs and gang-related violence.
Half a kilogram of heroin and a "large amount" of cash were seized from an address in Southwark and a kilogram of heroin, crack cocaine and £10,000 cash was taken in Bexleyheath, with four arrests made there, he said.
The major operation, spearheaded by the Met's newly-formed Trident Gang Crime Command, marks what senior officers have described as a "step change" in the way the force tackles gangs.
Scotland Yard revealed it has now committed 1,000 dedicated officers to fighting the problem, with the creation of the central Trident gang command and 19 new task forces to deal with local gang crime in problem boroughs across London.
Operation Trident was originally set up in 2000 to tackle gun crime in black communities across the capital and has gradually grown over the past decade.
Under the unit's expanded new remit it will retain the responsibility of investigating shootings, but also work alongside the borough task forces to proactively tackle gang crime, the Met said.
It will also have access to specialist resources including Operation Connect - the MPS unit set up to tackle violence driven by gang culture - and the Serious and Organised Crime Command.