Great train robber Ronnie Biggs could die if he does not respond to current treatment, his son said today.
Biggs, 79, who was refused parole yesterday, is being treated in a hospital in Norwich after being moved from a nearby prison on Sunday.
His son, Michael, said Biggs had pneumonia, plus fractures of the hip, pelvis and spine and was "deteriorating".
Mr Biggs was speaking after visiting his father at the Norfolk and Norwich Hospital.
"If he does not respond to the current treatment he is receiving there is a risk he could pass away," said Mr Biggs.
"He has a fractured hip and fractures to his spine and pelvis as well as pneumonia.
"The pneumonia is extremely strong in his body at the moment. He is in a lot of discomfort."
Mr Biggs said he could not understand Justice Secretary Jack Straw's decision not to grant his father parole.
He said Biggs was in such poor health that he posed no risk.
"I would urge Mr Straw to come down to the hospital and see him," added Mr Biggs.
"He cannot read or write. He cannot eat or drink."
Mr Biggs added: "He is extremely disappointed with Mr Straw's decision not to release him."
He said Biggs had been informed of Mr Straw's decision by the prison authorities yesterday.
"It was a political decision," added Mr Biggs.
"My father is more than ever now a political prisoner."
He added: "He has done his time."
Mr Biggs said he would continue to fight for his father's release.
He said he was hoping Mr Straw would review the decision and was considering the possibility of seeking a judicial review of the decision.
"Families stick together," said Mr Biggs.
"I will not give up the fight.
"Hope is the last thing to die and while there is hope we continue fighting.
"We are going to try for a judicial review.
"We are hopeful that Mr Straw will review his decision."