The detective who led the murder investigation has also criticised the call from the Chief Inspector of Prisons Sir David Ramsbotham.

The BBC's Jane Peel reports on the outrage following the comments

Sir David said Robert Thompson and Jon Venables, jailed for life for murder in 1993 and now aged 17, should be given "as early as possible a release" when they reached their 18th birthdays.

James's mother, Denise Fergus, said: "Why should Venables and Thompson be released after just a few years in comfortable surroundings while I serve the true life sentence without James?"

Former Det Sup Albert Kirkby: "It flies against what everyone's trying to achieve"

Liverpool lawyer Robin Makin, who represents James' father Ralph, said he was "horrified" by Sir David's comments about Thompson and Venables, who are now 17.

He said it was wrong for a Home Office employee to call for the boys' release when those attending the recent European Court hearing on the case were "embargoed from discussing the matter".

James Bulger was battered to death on a railway line

Retired Detective Superintendent Albert Kirby, who led the murder inquiry, described Sir David's comments as "inappropriate".

'Quite irresponsible'

He said: "We have got to bear in mind it's a very difficult and emotive issue currently being dealt with by the European courts.

"For him to sound off at this moment and to make these comments is quite irresponsible."

Sir David: Concerned about the boys' future

Sir David told the New Statesman magazine he had met Thompson - currently held in a social services secure unit - and had formed "a considerable admiration for the way he is being looked after and the way he has responded".

He said the pair - who are both 17 - should soon move from the care of social services to the Prison Service.

Sir David said: "What are we going to do with them? I would not wish them to go to some of the institutions I have seen.

"Once they have reached the age of adulthood (18), I would hope they would get as early as possible a release in order to give them some chance of making a life.

BBC Social Affairs Editor Niall Dickson: "Highly unusual for Chief Inspector of Prisons to comment on length of sentence"

"People say life shouldn't be easy for them in the light of what they did. I acknowledge that.

"But they did it at the age of nine (sic). I can't remember all my emotions at that age, and I'd be horrified if I was still held accountable for them."

Sentence increased

The boys were originally given an eight-year "tariff" for the killing - the period they must serve before being considered for release.

That term was increased to 10 years by the then Lord Chief Justice, Lord Taylor, and to 15 years by the then Home Secretary, Michael Howard.

Mr Howard's move was declared unlawful by the House of Lords, and current Home Secretary Jack Straw was invited to set a new tariff.

However, he is awaiting the outcome of an appeal in the European Court of Human Rights that the boys' trial in an adult court was unfair.

James' parents Denise and Ralph have since split up

Venables' solicitor, John Dickinson, said Sir David's comments were premature.

But he said Sir David was right to draw attention to the possible negative effects of detention in a young offenders' institution, such as violence, and drugs and sexual abuse.

Shadow home secretary Ann Widdecombe said it was not Sir David's job to comment on individual cases.

"He is supposed to inspect conditions in prisons and report on that," she told BBC Radio 4's Today programme.

But Paul Cavadino, policy director of the National Association for the Care and Resettlement of Offenders (Nacro), said Sir David had drawn attention to a real problem.

"When young offenders who have made real progress in local authority secure accommodation are transferred at 18 to the prison system this positive work can be undermined or even wrecked," he said.