Detectives are hunting smash and grab robbers after the capital suffered its 16th big 'moped-enabled' crime in just five months.

A gang of four suspects pulled up outside a designer second hand clothing store in leafy Knightsbridge, central London on two mopeds.

Three suspects dressed in black and wearing in motorbike helmets tried to kick and smash their way through the shop's front door as the fourth suspect blocked the road.