The notorious criminal spent decades on the run after breaking out of prison, and returned to Britain in 2001.
He suffered from poor health in his last few years, and died in the early hours of this morning, according to Sky News.
Ronnie Biggs, famous for his role in the Great Train Robbery, has died aged 84
Defiant: Biggs flashed the V-sign at photographers at the funeral of Bruce Reynolds in March
Biggs, from South London, was part of the gang which stole £2.6million from a train after forcing it to stop at a bridge in Buckinghamshire.
The daring nature of the crime made it instantly famous, with some regarding the thieves as 'Robin Hood' figures who only took money from banks which could afford the loss.
However, others point to the violence of the robbery, which left train driver Jack Mills unable to work again after he was hit over the head with a metal bar.
Bigg's death came less than 24 hours before the premiere of a BBC drama about the Great Train Robbery, 50 years after the heist.
Mugshot: Biggs was jailed for his role in the Great Train Robbery, but escaped after just 15 months
Taunting: Biggs pictured while on the run in Brazil, from where he returned in 2001
The 12 robbers were jailed for a combined total of more than 300 years after they stopped the Glasgow to Euston overnight mail train, which was carrying huge numbers of used bank notes, as it passed close to Cheddington on August 8 1963.
Two of the robbers, Charlie Wilson and Biggs, escaped jail, with Biggs spending 36 years on the run after returning to Britain in 2001 to face arrest.
He was eventually freed in 2009 on 'compassionate grounds' by then Justice Secretary Jack Straw.
The mastermind behind the gang, Bruce Reynolds, fled to Mexico and later Canada following the crime but returned to the UK and was jailed for 25 years in 1968.
He served 10 years before his release and died in February this year.
In July, just days before the 50th anniversary of the Great Train Robbery, Biggs said he had few regrets about the crime that made him a household name.
A new two-part drama series was due to start tonight on BBC1 to mark the 50th anniversary of the 'crime of the century'.
The first film, A Robber's Tale, focuses on the story of Bruce Reynolds as he masterminds the raid on the Royal Mail train.
The second installment, A Copper's Tale, tells the story from the perspective of DCS Tommy Butler, the police officer leading the investigation aimed at bringing the gang to justice.
