One amazing day at the Dome: Gang of 12 arrested in £350m diamond robbery

A daring attempt to stage the world's biggest robbery and steal diamonds worth £350m from the Millennium Dome was foiled by Scotland Yard yesterday.

A daring attempt to stage the world's biggest robbery and steal diamonds worth £350m from the Millennium Dome was foiled by Scotland Yard yesterday.

Twelve suspected robbers were arrested after undercover officers ambushed the gang as they attempted to steal 12 of the world's finest diamonds.

Four men dressed as workmen used a stolen digger to smash their way into the Dome's Money Zone at 9.30am. They let off smoke bombs and used sledgehammers and a nail gun to try to break into the case holding the gems.

But they were caught by dozens of armed officers, disguised as cleaners with guns hidden in binliners, as part of a carefully planned trap.

The gang, who had a speedboat waiting on the Thames, had been under surveillance by the Metropolitan Police Flying Squad for months.

No one was injured, although a party of schoolchildren trapped inside the Dome in Greenwich, south-east London, huddled in a room and sang hymns as the raid unfolded.

Det Supt Jon Shatford, who led the police operation, said the gang were audacious and potentially very dangerous.

"If this had been carried out in accordance with their wishes this would have been the largest robbery in the world," he said.

Four people were arrested in the Money Zone in which the De Beers diamonds - including the spectacular 203-carat Millennium Star - have been on display this year. The priceless diamonds had been replaced with a set of crystal dummies on Monday.

A man was arrested on a power boat at the Millennium Pier. Another was arrested on the north side of the Thames with a getaway vehicle.

Later, Kent police said officers from its serious crime unit, with armed support officers, arrested six more people in two raids on addresses in the villages of Collier Street and Horsmonden. All those arrested were last night being questioned by detectives.