Two young men with machetes and drugs were arrested when police on a routine patrol stopped a car in Merton High Street at five past midnight last night.
The 17-year-old Vauxhall Corsa passenger tried to make a break for it but his getaway was foiled when he tripped over the large machete he has hidden in his trouser leg.
Police arrested him after he tripped over the weapon and a substance believed to be cannabis and a set of scales were recovered from the car.
The driver, who is in his early 20s, was also arrested and both men remain in custody at a south London police station.