The haul included gold, diamond and sapphire jewelry, cash and other valuables belonging to local jewelers in Hatton Garden.
Carl Wood, William Lincoln and Hugh Doyle, aged 48 to 60, were found guilty Thursday (local time) of being involved in the burglary. A fourth man, taxi driver Jon Harbinson, was cleared. Four other men aged 58 to 76, described as the ringleaders of the gang, pleaded guilty earlier.
The men chose the Easter holiday weekend last year to carry out the crime, and were able to secure their break-in to a safe deposit facility in the jewelry quarter over two nights virtually without anyone noticing.
Disguised as workmen, the thieves entered carrying bags and wheeled garbage bins for carrying off the booty.
Police said that on the first night, the gang climbed (around four metres down an elevator shaft but failed to access the deposit boxes. They returned the following night with more equipment, and successfully climbed into the basement vault through a hole they drilled in a thick cement wall. They then spent the whole night in the vault ransacking 73 deposit boxes.
It wasn't until security workers returned to work on Tuesday that the crime was discovered. Police have apologised for failing to respond to a midnight alarm that sounded at the start of the holiday weekend.
Police described the men as "career criminals" " two of them were previously convicted of robberies " and stressed that their age didn't make them any less dangerous. Despite their experience, some of the men were later recorded boasting about their raid, leading to their arrest.
Most of the stolen goods have not been recovered, and one of the key suspects " a man known only as "Basil" who let the others into the building " hasn't yet been identified and police are still investigating his whereabouts.
All the men are due to be sentenced on March 7.
