More than 80 suspects were arrested during a three-day crackdown on criminal gangs fuelling knife violence across London and the Homes Counties.
Hundreds of police from five forces set up checkpoints on motorways and arterial roads, pulling over cars flagged up on the number plate database to search for drugs, weapons and high-performance stolen vehicles.
The Met said criminals often operate across different policing areas in quick succession using false plates to avoid detection.
Operation Pandilla involved officers from the Met, Hertfordshire, British Transport, Surrey and Thames Valley, targeting the M25, M1, M4, North and South Circulars and rail networks.
Scotland Yard said 85 people were detained for knife, weapons and drugs offences, 57 vehicles seized and 337 stop-and-searches conducted up to April 28.
Chief Inspector Rob Ranstead, who led the Met’s operation, said: “Organised crime, including county lines drug supply and criminals committing burglaries and robberies, are key drivers of violence in our communities. And offenders often exploit and target the vulnerable.
“Tackling violent crime and the supply of drugs is a top priority. The key aim of this operation was to stop drugs and weapons being brought onto the streets. Preventing these crimes, while also safeguarding vulnerable individuals on the cusp of violence, is paramount.”
He added: “Our determination remains strong and weâ¯will continue to work with our partners, and use every power and tactic available to serve and protect our communities.
“We will continue to deny the use of the roads and railway for violent and predatory people, drug dealers and those involved in county lines gangs and organised crime to operate.”
