A total of 21 suspected gang members were arrested in dawn raids across Barnet as police stepped up the fight against gang crime.
A loaded 9mm handgun as well as £6,000 in cash and a “large quantity” of class A drugs were found at one address during the raids.
Detective Inspector Will Cole, from the Barnet Gangs Unit, said the borough’s “most harmful offenders” had been targeted.
He said: “We have invested considerable resources in addressing this problem, which has grown across London and we are now starting to see the fruits of our labour."
Police have only this week released details of the top secret raids which took place at 20 addresses on March 16 and 22.
Officers from the Met’s Territorial Support Group wore riot gear and used rapid-entry methods to gain entry to the properties at just before daybreak.
The raids were preceded by six months of detailed investigations, some of which used intelligence from local communities.
Simultaneous dawn raids also took place at addresses in Brent, Harrow and Ealing, under the operation led by the Met’s Trident and Area Crime Command unit, which deals specifically with gang crime.
Across all four boroughs a total of 44 addresses were searched, 42 people were arrested, and 34 people have since been charged with offences including possession with intent to supply class A and B drugs, possession of a firearm and money laundering.
Detective Inspector Beverly Kofi, who led the operation said: “The message to those involved in gangs anywhere in London is that if you involve yourself in this kind of criminal activity, then we will hold you to account. We will target you and you will be arrested and put before the courts.
“There is always a way out of a gang, however hard it might seem, and help is available from the police and others for anyone who is serious about getting themselves out of that situation.”
If you have any information about gang crime or those involved call Crimestoppers - an independent charity - anonymously on 0800 555 111. In an emergency always dial 999.