It's the biggest heist in British history and yet 16 years on, the mystery of the Northern Bank robbery in Belfast remains unsolved despite a huge international police investigation.
Now, a new BBC documentary takes an in-depth look at the robbery that almost derailed the already fragile Northern Ireland peace process.
In a highly sophisticated operation which happened just days before Christmas in December 2004, the gang took two families hostage for 24 hours, forcing two bank employees to rob £26.5M from the cash centre.
Heist: The Northern Bank Robbery takes a fresh look at the heist and the questions that remain unanswered. With exclusive access to new source material - including police 999 calls along with internal bank CCTV, Northern Ireland journalists Darragh McIntyre and Sam McBride come together to shed new light on one of the most notorious cases in UK-Irish criminal history.
Through interviews with key players - in politics, policing and financial crime - they uncover what happened to the main suspects in the cross-border police investigation and ask whether the robbery may, inadvertently, have helped the peace process.
Alongside interviews with former Taoiseach Bertie Ahern, former PSNI Chief Constable Sir Hugh Orde, Dr Mitchell Reiss, US Special Envoy to Northern Ireland under Bush administration and others, the film also features an interview with Ted Cunningham, the Cork-based financier who was the first person convicted in relation to the Northern Bank robbery.
He was charged with money laundering in relation and today insists he is innocent of all charges.
Speaking in the hour long programme, Cunningham vows to 'fight to the day he dies' and how this 'is not the end of the story.'
He said: "I know who I got the money from and it was not from the Northern Bank."
Despite admitting to two counts of money laundering in his second trial, Cunningham maintains his innocence saying he 'feared for his life'.
"As far as I'm concerned the State they needed a fall guy, I'm the victim," he added.
Heist: The Northern Bank Robbery airs on Monday, 3 May on BBC One NI at 9pm.
