The Government was today attacked in the Lords for its decision to refuse parole to the Great Train Robber Ronnie Biggs.

Biggs, 79, is being treated at the Norfolk and Norwich Hospital after being moved from a nearby prison.

Justice Secretary Jack Straw last week rejected a Parole Board recommendation that Biggs be released, saying he was "wholly unrepentant" about his crimes.

But Labour former minister Lord Dubs said at question time: "Mr Biggs is old, he is very ill, he is most unlikely to do any harm to anybody and is no danger to society and the public would not protest at his early release, particularly under supervision."

He said he did not "condone" Mr Biggs' crime but asked justice minister Lord Bach: "What is the purpose of keeping people like him in our over-crowded jails?"

Lord Bach said that he could "of course confirm" that Mr Biggs was "elderly and not in good health".

But he added: "The Parole Board itself said this: 'What has quite plainly reduced enormously is his capacity to reoffend... but the Parole Board panel is not persuaded that risk arising from association with criminal peers and consequent indirect involvement in offending is necessarily equally low'."

He said the Justice Secretary considered the judgment to be of "considerable importance" in coming to his decision. Mr Straw had determined that "the risk of harm presented by Mr Biggs was such that it might not be safely managed in the community" after taking into account all the facts of the case.

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 escaped from Wandsworth prison in south-west London by climbing a 30ft wall and fleeing in a furniture van.

After more than 30 years, living in Spain, Australia and Brazil, he returned to the UK in 2001 was put back in prison.

Lord Elystan-Morgan, a retired judge, said there were a number of "aggravatory features" in Biggs' case but he had returned "voluntarily".

In reply, Lord Bach said: "It is right to say he returned voluntarily some 36 years after he committed the offence of escaping from HMP Wandsworth."

He added that Biggs would have finished his sentence "a long time ago" if he had not escaped.

Lord Thomas of Gresford, for Liberal Democrats, said the decision "should have been made by the Parole Board" and Mr Straw's intervention was "a populist move we should deplore".

Lord Bach said he rejected "utterly" the idea it was a populist move.