Many of the criminals were well past retirement age, but they carried out an incredibly ambitious robbery, cutting through metal bars and boring through a 50-centimeter (20-inch) reinforced concrete wall to climb into a vault.
The caper took place during the long Easter weekend. As Londoners prepared to enjoy a couple of days off, the gang was setting into motion the audacious heist that had been three years in the planning.
Their target was the Hatton Garden Safe Deposit Co., in the heart of the city's diamond district.
Disguised, in plain sight
The family-owned vault in the basement of the building had been used by jewelers since the 1940s to store gold, precious stones and cash.
The looters posed as gas repairmen, complete with high visibility vests and hard hats which not only made them look innocuous, but also helped to conceal their identities from the countless security cameras in the area.
A fire escape at the side of the building served as their entry point. Once inside, the men used an elevator shaft to access the basement, where they cut through the bars and drilled through the wall to climb into the vault.
They raided dozens of safety deposit boxes and loaded nearly $22 million worth of valuables into wheelie bins, which they casually loaded, in plain sight, into a waiting white transit van.
But the heist wasn't as straightforward as the gang would have liked.
During a seven-week trial at London's Woolwich Crown Court, the jury heard the thieves were only partly successful in drilling the hole on the first night and had to return to finish the job.
In all, they spent four days carrying out the burglary.
As a measure of the gang's experience and careful planning, police were unable to find any forensic trace of the perpetrators.
In the end, it was mobile and land-line phone data that gave investigators their lead on several suspects, who were then put under surveillance.
Police swooped in after witnessing the movement of some of the stolen goods, arresting nine men in raids in London and the neighboring county of Kent.
Eight of the suspects, aged between 42 and 76 were charged with conspiracy to burgle.
The men identified as the ringleaders -- Brian Reader, 76, Terry Perkins, 67, John "Kenny" Collins, 75, and Dan Jones, 60 -- all pleaded guilty before the case went to trial and are now awaiting sentence.
Prosecutors said the four men who pleaded guilty in September were "a close-knit group of experienced criminals."
"They were career criminals. They were callous," said London Metropolitan Police Detective Superintendant Craig Turner.
"They had no consideration for those victims of crime whatsoever. I'd ask members of the public to look past their actual age. They were well-schooled individuals in relation to criminal activity and members of the public should look past the glamorization of this crime."
Carl Wood, 58, and William "Billy" Lincoln, 60, were found guilty Thursday of conspiracy to burgle and to transfer criminal property. Hugh Doyle, 48, was found guilty of the latter charge.
Jon Harbinson, Lincoln's nephew, was found not guilty on Thursday.
But that is not the end of the case.
Police have only recovered around a third of the stolen items.
Some $14 million worth of valuables are still missing, and a mysterious red-haired suspect referred to in court as "Basil" remains on the run.