Secret existence that is shared only with the Bulger killers

Living a secret existence to all but a few trusted officials and relatives is something that Mary Bell and her daughter share with the two killers of James Bulger, top level police informers, and spies.

As part of a package of measures designed to protect their identity Bell and her daughter will have been given a new home, new passports, and new national insurance and social security documents. Bell has a detailed false history, researched by the dangerous offenders' unit in the Home Office.

The couple yesterday joined Jon Venables and Robert Thompson, who were released in 2001 after serving eight years for the murder of two-year-old Bulger, as the only people to win lifelong anonymity. The procedures and safeguards offered to Bell and her daughter have been largely developed from the police and security service's experience in protecting informers, witnesses, and agents. At least seven police forces run their own protection units for informers and witnesses at risk of violence. A further 12 are believed to have specialist protection officers.

Like the Bulger killers, Bell has been trained to keep her identity secret, and the secret is shared only by about 20 people. The new names will have been flagged on all confidential police computer databases, so that if they are stopped by police the local chief constable and a special Home Office unit at the Prison Service in London will be immediately informed.

Their homes would be expected to have a hotline or panic button to the local police station in the event of any signs of vigilante action. Any fears that their identities had been compromised could result in the whole process starting again with new names, new life histories and new homes and jobs.

Bell, who has changed her identity on at least three occasions, and her daughter have already suffered the consequences of being recognised. The 18-year-old has moved many times during her childhood and had the alarming experience of being removed, aged four, from a school where she was unacceptable as a pupil because of her true identity.

Bell was tracked down in 1998 by a tabloid newspaper after she was paid £50,000 to co-operate on a book about her crimes called Cries Unheard by Gitta Sereny. The ensuing media storm forced Bell and her daughter to move to a safe address. Ms Sereny, who yesterday described Bell as a "pal" said: "Now she wants to live quietly."