A violent gang clash was narrowly averted when police swooped on Hounslow town centre after receiving a tip-off about a fight between two rival gangs.
Hounslow Police ordered 12 youngsters to leave the High Street while another 23 were searched and arrested two people, one for assault and one for possession of drugs.
Supt Simon Phipps said: "There is considerable media coverage about the threat of serious violence and the detrimental impact upon the quality of life of Londoners.
"On this occasion, Hounslow Police made proportionate use of the extensive powers available to reduce and prevent violence.
"People who live in, work in or visit Hounslow town centre were able to go about their business without threat and intimidation by a small minority of violent offenders."
In another move to deter the use of knives and weapons in the town centre last Friday, police set up a metal-detecting 'search arch' at the entrance to the Treaty Centre.
More than 200 people passed through the arch, where they were greeted by Treaty Centre security staff and police officers.
Fifteen people were searched but no weapons were found during the exercise.