A gang of aging criminals that carried out an audacious multimillion pound raid on a safe-deposit business in London's jewelry district last year were jailed Wednesday for their role in the largest-ever burglary in English legal history.

As the gang, led by pensioners who had spent their lives in crime, were sentenced for the daring heist at the Hatton Garden Safety Deposit building last Easter, police reissued an appeal to find a mystery man known as "Basil," who was at the center of the plot, and is believed to be connected to the whereabouts of much of the stolen loot.

"It is clear that the burglary at the heart of this case stands in a class of its own in the scale of the ambition, the detail of the planning, the level of preparation, the organizing of the team to carry it out and in terms of the value of property stolen," said Judge Christopher Kinch.