London - The family of Ronnie Biggs, Britain's "Great Train Robber," Thursday made a fresh appeal for his release from prison just days before his 80th birthday.

Biggs' son, Michael, said legal representatives had asked the government to consider the prisoner's release on compassionate grounds.

On July 1, Justice Secretary Jack Straw rejected an application for parole on the grounds that Biggs had been "wholly unrepentant" about his role in the 1963 raid on a postal train.

But two days ago, Biggs was transferred to hospital from his prison in Norwich, eastern Britain, suffering from "severe pneumonia."

According to his son, Biggs' life "hangs in the balance" and doctors at Norwich University Hospital say they have "little hope of recovery."

Biggs, who turns 80 on August 8, has suffered several strokes and is unable to eat, walk or speak without help, his family says.

Prison Service officials will now consider the request for his release on compassionate grounds.

Biggs was a member of a 15-strong gang which attacked the Glasgow to London mail train in Buckinghamshire, north of London, on August 8, 1963, getting away with a record haul at the time.

He was given a 30-year jail term but escaped from London's Wandsworth prison after 15 months, eluding capture by Scotland Yard for more than 36 years.

During that time, Biggs lived in France, Australia and Brazil, from where he returned voluntarily in 2001. (dpa)