It's the sort of thing that could only happen in England, a kind of Carry On Up The Dome

John McVicar

Detective Chief Superintendent Jon Shatford told the BBC he understood public concerns about the way the gang were caught - but "the bigger risk would have been to let those criminals go free".

"It was a very tough call. We made contingencies all morning long, making sure the people were taken out of the way, and police were between the public [and the robbers].

"There were risks. We mitigated the risks but we could never eliminate them."

He said the police did not know exactly what the men were planning to do - and had never expected them to use the JCB to smash through the Dome, "because it was too dangerous".

He added he had, however, believed the group were going to be armed, as they were a "professional and dangerous" group of criminals.

The men convicted of conspiracy to rob are:

• Aldo Ciarrocchi, 32, of Bermondsey, London, jailed for 15 years
  
• William Cockram, 49, of Catford, London, jailed for 18 years
  
• Raymond Betson, 40, of Chatham, Kent, jailed for 18 years
  
• Robert Adams, 57, no fixed address, jailed for 15 years

A fifth man, Kevin Meredith, 34, of Aucklands Drive, Brighton, was cleared of conspiracy to rob but convicted of conspiracy to steal and jailed for five years.

Tip-off

During the trial, the court heard how the gang had been under surveillance for five months, following a tip-off from a police informer.

Shatford: "Contingencies" to keep the public safe

On the morning of the robbery, the Dome had opened to members of the public as usual.

Armed with sledgehammers, nail guns, ammonia and smoke grenades, the gang smashed into the Dome on the earthmover, and raced it to the diamond exhibition.

Ciarrocchi threw smoke grenades towards tourists and staff to create confusion, while Adams and Cockram attempted to break the display cases housing the 12 rare diamonds.

But unknown to the gang, police had switched the diamonds for replicas - and more than 100 armed officers were lying in wait to catch them red-handed.

Robbers had smashed the case when police pounced

Ex-criminal and crime author John McVicar was amused by suggestions that either the diamonds or the tourists were ever in danger - calling the whole incident "farcical".

He told the BBC: "It's the sort of thing that could only happen in England, a kind of Carry On Up The Dome.

"The diamonds were just paste, and there's this group going in for James Bond antics... and they're not even armed.

"The children were cocooned in the Mind Zone.

"I bet Sean Connery and Michael Caine are stirring in their Riviera homes for the film script on this one."

But he conceded: "This is a heavy-duty gang, and they have got away with a lot of other heists."