Ronnie Biggs, whose role in the 1963 "Great Train Robbery" made him one of Britain's most infamous criminals, have been freed from jail today on compassionate grounds.
His son Michael Biggs said he will stay in hospital for at least a week following his release.
Michael Biggs said his father, who has pneumonia, needed minor surgery and would not be fit to move until at least mid-August.
Britain's Justice Secretary Jack Straw said yesterday he had decided to release Biggs on compassionate grounds.
Biggs, who will be 80 tomorrow, is being treated at the Norfolk and Norwich hospital in Norwich after being moved from Norwich Prison.
Speaking outside the hospital before his father's release, Mr Biggs said he expected him to undergo minor surgery next week. "We are looking at at least a week before any decision can be made about even considering when he can leave the hospital," added Mr Biggs. "It will just be good to have him as Ronald Arthur Biggs, not a prison number."
Biggs escaped from prison in the 1960s and spent decades as a fugitive in Brazil where his playboy lifestyle and cocky defiance of the British authorities made him a criminal legend.
Biggs returned to Britain voluntarily in 2001 and has been in jail ever since, but his declining health has stirred debate about whether he should be released after serving 10 years of a 30-year sentence.
"Mr Ronald Biggs has been informed today of my decision regarding his application for compassionate release on medical grounds," Mr Straw said yesterday, reversing a decision a month ago to refuse him parole.
"The medical evidence clearly shows that Mr Biggs is very ill and that his condition has deteriorated recently, culminating in his re-admission to hospital. His condition is not expected to improve," he added.
Along with 11 other gang members, Biggs robbed a Glasgow-to-London mail train in 1963 and stole £2.6 million - about £30 million in today's money. The crime became known as "The Great Train Robbery." Biggs was caught and sentenced the following year but escaped from prison after just 15 months.
He used his share of the money to pay for plastic surgery and papers for a passage to Australia where he returned to his old job of carpenter and decorator. He later fled to Brazil via Panama and Venezuela. He surrendered to police in 2001 after 36 years on the run.
Mr Straw said he had made the initial decision to refuse parole principally because Biggs had shown "no remorse for his crimes nor respect for the punishments given to him."
But Mr Straw said he had changed his mind after considering the prisoner's health, specifically whether death was likely to occur soon and whether the prisoner was bedridden or incapacitated.
The Prison Reform Trust welcomed the news and said the jail terms of hundreds of elderly prisoners should also be reviewed.
Agencies