Images of the Bulger killers shocked the nation

The pair, now aged 18, have had the privacy injunction which has protected them since their 1993 trial extended beyond the end of their in custody.

Even though the media in England and Wales is prevented from disclosing the boys' whereabouts, news organisations elsewhere - and their websites - will be free to pursue the duo.

Paul Cavadino of the National Association for the Care and Resettlement of Offenders says the boys are at "grave risk of vigilante attack".

Familiar faces

In the initial period after their arrest, Thompson and Venables were referred to as Child A and Child B. However, their names and faces were soon splashed across newspapers and TV screens.

"Because the identity and photographs of the pair were released at the time of the trial, their rehabilitation has been made much harder - putting them at risk of reprisals," says Mr Cavadino.

Ralph Bulger, James's father, opposes releasing the killers

Unsurprisingly, the boys no longer resemble their youthful selves - or speak like them.

However, to ensure they can begin new lives in the outside world, the two will have to be given intricate false identities.

Harry Fletcher, assistant secretary general of the National Association of Probation Officers, says the Bulger case is so unusual there is no real precedent for the release of such high-profile offenders.

Historical fiction

As well as assumed names, the pair will be given "pre-histories" so that their identities can withstand the scrutiny of future neighbours or colleagues.

In 1997, the cover of the IRA informer Martin McGartland was blown when he was charged with a traffic offence and found to possess a clutch of false driving licences.

Although he embarked on yet another new life in Tyneside, Mr McGartland was badly injured in a gun attack last year.

Martin McGartland's cover was blown

As well as new names, and the passports and national insurance numbers which go with them, Thompson and Venables will be taken to "safe houses" - presumably well away from Bootle, where they committed their crime.

It has even been reported that the pair have been offered the chance to emigrate from the UK.

The resettlement may prove especially complex should the killers and their families decide to retain close links.

Family ties

Albert Kirby, a retired detective who led the Bulger investigation, has said the boys would have to sever even their parental links or force their immediate families to undergo similar identity changes.

"Their whole families will have to sever all contact with their former friends and associates," he said.

There are few precedents for the Bulger case

When Danielle Cable, a witness to Kenneth Noye's murder of Stephen Cameron on a motorway slip road, entered a witness protection programme, she wasn't permitted to see her mother for the first four months.

Her phone calls were strictly limited and letters routed so that they took several months to arrive.

Thompson and Venables may well need such "extreme measures" if their new identities are to prove viable.

Bill Norris, associate director of the media ethics charity the Press Wise Trust, says legal protection is vital.

Staying hidden

"History proves it is extremely difficult to hide away without a legal injunction. This was shown in the Mary Bell case."

Mary Bell, who was imprisoned aged 11 for the killing of two children in 1968, was found by reporters within eight years of being released.

Her details were legally suppressed, when Bell argued disclosure would harm her young daughter.

Mary Bell was tracked down by reporters

Although the whereabouts of Thompson and Venables will be known to only a small circle - under the eye of "a highly-experienced, highly-motivated and senior figure" from the probation service, according to Mr Fletcher - determined journalists may not be foiled.

"Journalists rely on tip-offs. Money will be at the root, and newspapers will pay for the information," says Mr Norris.

"Where money is involved, nothing is a secret if it's shared by more than one person."

Mr Norris also worries we will see a repeat of the News of the World's "naming and shaming" of paedophiles - which sparked a debate about offender rehabilitation and saw several cases of mistaken identity.

"Anyone who happens to look like them or live near them might be put at risk," he says.

"Just like Thompson and Venables, their lives would be put at risk, without a doubt."