Officials are considering a plea by "Great Train Robber" Ronnie Biggs for release on “compassionate grounds”, the Ministry of Justice confirmed today.
Biggs, who turns 80 next week, is in hospital suffering from severe pneumonia.
His legal representatives made the plea for release after Biggs was taken from his cell to Norfolk and Norwich University Hospital earlier this week.
At the time, his son Michael said doctors had told him there was "not much hope" for his father.
The Prison Service confirmed the request had been received and would be dealt with as soon as possible.
A spokesman said: "We can confirm that an application for the early release on compassionate grounds of a prisoner at HMP Norwich has been received by the Public Protection Casework Section in the National Offender Management Service.
"We do not discuss the cases of individual prisoners.
"All applications are processed as soon as we reasonably can and each is carefully considered on its merits against the published criteria."
Four weeks ago Justice Secretary Jack Straw refused Biggs's request for parole, saying he was "wholly unrepentant" about his crimes.
Biggs, from Lambeth, south London, was a member of a 15-strong gang which attacked the Glasgow to London mail train at Ledburn, Buckinghamshire, in August 1963, and made off with #2.6 million in used banknotes.
He was given a 30-year sentence but after 15 months he escaped from Wandsworth prison in south west London by climbing a 30ft wall and fleeing in a furniture van.
Biggs was on the run for more than 30 years, living in Australia and Brazil before returning to the UK voluntarily in 2001 in search of medical treatment.
He was locked up in Belmarsh high security prison on his return before being moved to a specialist medical unit at Norwich prison.
Earlier requests for release on compassionate grounds were refused in 2006, 2007 and last month.
PA