Police discovered an enormous stash of cocaine in three safes hidden behind a false wall in a lock-up building.
Officers from the Metropolitan Police's central task force stopped a 26-year-old man in Goffs Oak, Hertfordshire, yesterday afternoon, after he left the building in St James's Road.
They found he had a kilogram of cocaine on him, and the man was arrested on suspicion of possession with intent to supply class A drugs.
Searching the premises officers found three safes behind a false wall, which contained 29kg of cocaine, scales and other drugs paraphernalia.
The man was taken to a north London police station, where he remains in custody.