One of the Millennium Dome robbers has been jailed for 13 years after he tried to raid a cash depot but botched it.
Raymond Betson and unknown offenders targeted a Loomis cash depot in Swanley but drove a digger into the wrong wall.
He was convicted of attempted robbery in a trial at Maidstone Crown Court. Police are still looking for others involved in the March 2012 raid.
Betson, 52, from Folkestone, was one of several men jailed over the attempted £200m Millennium Dome diamond heist.
Kent Police described the botched robbery in Swanley as an attempted multi-million pound raid.
Det Insp Rob Haines said: "Betson wanted to make a lot of money quickly and was significantly involved."
He said the crime displayed a level of violence, planning and organisation with the use of a heavy-duty digger, and weapons such as baseball bats and a getaway vehicle involved.
But he said: "What went from an armed robbery quickly turned into a farce because they knocked down the wrong wall, then searched an empty warehouse and managed to render the getaway vehicle useless as they fled the scene, discarding equipment nearby."
Officers said a Mitsubishi 4x4 was found grounded on a dip in a field with a two-way radio, baseball bat and large white bags inside.
A balaclava, snood and stopwatch were found in a nearby bush.
Police searched Betson's house in Clifton Crescent and arrested him after DNA from the snood and balaclava provided a near-perfect match to him, Det Insp Haines said.
He said there was less than a one-in-a-billion chance that the DNA could match anyone else.
In the search for the other five offenders, Kent Police have named Karl Patrick Delaney, 37, formerly of Sheerness, as a person they want to trace. Officers believe he has fled to the Republic of Ireland.
Betson was found guilty of conspiring to rob after the Dome diamond heist and jailed for 18 years in 2002. His sentence was later reduced to 15 years.
At the Dome, several men smashed their way into the site in a digger, where police were to catch them red-handed.
One man waited in a speedboat to help them escape across the Thames, another threw smoke grenades, and two raced into the exhibition. Betson stayed in the JCB.