Ten people, aged between 21 and 58, were arrested after 250 officers carried out warrants at 16 addresses on Wednesday.
The arrests came after a three month long proactive investigation identified violent gang activity operating a supply of class A drugs in the West Drayton area.
Intelligence also suggested a new county line was being established, running into nearby counties.
Officers searched addresses in west London where they seized class A drugs, suspected Heroin and Crack Cocaine, a stun gun and a number of stolen tools.
Detective Chief Inspector Rav Thind, from the West Area Command Unit, said: “People organising the supply of drugs have detrimental impacts on our society, exacerbating addictions, taking advantage of people in very vulnerable situations and often turning to violence, all for a profit.
“I hope that our work with 250 officers this morning shows the public we do not accept criminality and that we are determined to crackdown on the supply of drugs within London and across to other counties.
“My ask of the public is to speak to local officers if you have any questions or concerns about crime in your neighbourhoods. By residents reporting criminality and violence, we can build a better policing plan to tackle issues affecting our communities.”