The men are accused of trying to steal diamonds worth �200m

Four of the men - Aldo Ciarrocchi, 32, of Bermondsey, south-east London, Raymond Betson, 40, of Chatham, Kent, William Cockran, 49, from Catford, south-east London, and Robert Adams, 57, of no fixed address - all deny conspiracy to rob.

But the four have admitted the lesser charge of conspiring to steal.

Boat skipper Kevin Meredith, 34, of Brighton, East Sussex, denies both conspiring to rob and conspiring to steal.

Judge Coombe told the jury Mr Meredith had said he had been under duress and had had no idea where he was to drive the boat or in what connection.

Getaway boat

The four men have said they thought they could take the diamonds without interference - which would be a case of straightforward theft, the judge explained.

The prosecution alleges they are just trying to cut their losses having been arrested at the scene.

It also alleges the gang intended to snatch the diamonds by smashing their way into the De Beers exhibition vault on an earthmover and escaping across the River Thames by speedboat.

The judge warned the jury members to put the question of sentences out of their minds when reaching verdicts.