Supergrasses: Life on the run

Michelle Hogg, who gave evidence against her Securitas co-conspirators, now joins many others in the Witness Protection Unit. Michael Gillard reports

Marshall Cook knows what it means to live life looking over his shoulder. He has spent half a lifetime on guard against the bullet he knows will come his way if he lets his guard slip. These are not the delusions of an underworld understudy.

Cook is a supergrass, whose activities as a government witness in many ways rivalled his earlier antics making unauthorised cash withdrawals from bank and Securitas vans. He has spent almost a decade in the witness-protection programme.

Like Michelle Hogg, who is starting a new life in "the programme" after giving damning evidence against five of the gang behind the Securitas raid – Britain's largest ever cash robbery – he lives with the constant knowledge that there are people who want him dead.

They are willing to put in the effort to get what they want. On one occasion, when he lifted the cover off the motorbike he'd parked outside his family home, he found it was snagging on something. He stopped pulling to see what was holding the cover back: it was a live hand grenade, primed to explode as the cover was lifted off the motorbike.

As a successful armed robber, the fortysomething, Jamaican-born west Londoner is no stranger to casual, extreme violence. Cook is not his real name but one of a handful given to him by the police.

Hogg, a 33-year-old from Woolwich, south-east London, will probably have to adopt a similar change of name to avoid falling victim to the multimillion-pound price reported to have been put on her head. She was a vital first piece in the puzzle that confronted police after the £53m heist at Tonbridge, Kent, nearly two years ago. She had created disguises for four of the robbers so they could impersonate police officers without being identified afterwards. Within 24 hours of the robbery, a tip-off led detectives to her front door.

Her initial protestations of innocence were disbelieved and she was eventually charged with conspiracy to rob and kidnap. Halfway through the Old Bailey trial, her defence team approached the Crown Prosecution Service looking for a deal in return for giving evidence against her co-defendants. This route is better known in criminal circles as "going QE" (Queen's Evidence) or "rolling over" and is not a decision taken lightly.

Hogg's offer was accepted and her detailed description of how she made the disguises proved invaluable in securing the five convictions. She is likely to be called on again to give evidence as other members of the robbery gang are still at large.

She lives with 24-hour police protection and will eventually assume a completely new identity in the programme. The scheme is designed to protect innocent and guilty people whom the state believes have crucial evidence to give in important cases. It can mean a new life in a new part of the country or in a new country altogether for the protected witnesses and any family. Many of these witnesses are men like Cook – career criminals who have turned on their associates to secure a better deal for themselves.

Cook said Scotland Yard's anti-corruption squad held out promises to him in 1998, when they were desperate to have him turn supergrass against a group of Flying Squad officers in east London. He said he was promised "protection for life", a new identity and relocation. "Being in the Witness Protection Unit is the comfort zone," he said. "Time and again you hear about people coming out and the next day getting shot."

After the Flying Squad trials and (unsuccessful) appeals ended, in 2003 he signed a memorandum of understanding drafted by the Met. He was then relocated under a new identity provided by its Witness Protection Unit (WPU).

Everything but Cook's DNA was erased from all government databases. He received a new passport, new NHS details and a new national insurance card and driving licence. Cook says he was also given a small business loan of a few thousand pounds at zero interest, which he would have to repay when he was back on his feet.

Under the agreement, Cook had to abide by certain rules above and beyond not going back to a life of crime. One condition he found hard to comply with was not being allowed to travel to certain parts of London without prior authorisation. The WPU operated a warning system whereby any infringement would result in a yellow card being issued against him. Always testing the system, he admits to receiving several yellows but no red ones.

Not all members of his family wanted to take the dramatic step and go into the programme. However, Cook did persuade the police to put alternative security measures in place, including panic buttons in their homes which are linked to the nearest police station.

Over all, the police have a good record at protecting witnesses, but the numbers needing protection are growing and difficulties with the system are rising too. In 1999, IRA supergrass Martin McGartland was shot six times in an attack at his new home in Whitley Bay, Northumberland. The house was part of a new cover given to him when the IRA uncovered his activities as a British informant in 1991 and he was forced to jump from the third floor of a building to escape execution. He has since been moved to a new secret location.

In May 2004, Maxine Carr, jailed for perverting the course of justice after providing a false alibi for her boyfriend, Soham murderer Ian Huntley, received a lifetime injunction from the High Court. It now safeguards her new identity after she received death threats. Similarly, anonymity was granted to child killer Mary Bell after she was released from prison in 1980.

Danielle Cable, who witnessed the killing of her boyfriend Stephen Cameron by gangster Kenneth Noye in 1996, has been living under witness protection since Noye was convicted in 2000. Another witness to the murder, Alan Decabral, declined the offer of protection and was found shot dead in his car.

Detectives claim that real threats to witnesses are few and far between, but that is little consolation to people such as Hogg or Cook whose lives are on the line.

Late in 2005, Cook began to worry about his future safety. That year there had been a number of troubling incidents that suggested, at least to Cook, that his new life had been compromised. Someone he had grown up with recognised him while he was working; he received threatening messages on an old mobile; there were attempts to jimmy open his front door; and finally, at a dance someone connected to a criminal gang he had betrayed pulled a knife on him. "I kept cool and he pulled away," he says.

He reported these incidents to the Witness Protection Unit, whose officers would meet him every so often at roadside cafés and other unglamorous locations. They advised him to report matters to the local police. But Cook felt that the Met was trying to drop him from the programme.

In a follow-up meeting he says he was told his contribution to the criminal justice system had been "crucial" but the risk to him was now deemed "low". The WPU brought along a document which they asked him to sign there and then. In effect, he was being asked to withdraw voluntarily from the programme. Cook was told that under the new Serious and Organised Crime Act, the police could cancel a person's protection at their discretion. This would also mean the end of the limited security measures for his estranged family living outside the programme.

Cook didn't accept the risk assessment on his life. He doesn't fear retribution from the Flying Squad officers he helped to convict and who are now free. It is the London gangsters who cause him real concern. "I know there is a bullet out there for me," he says.

He has good reason to fear one gangster in particular, detailed in police reports seen by The Independent on Sunday. Cook's evidence led to convictions of the gangster's associates for robbery. The man, who is regarded by the police as one of the UK's premier armed robbers, was behind the attempt to kill Cook with the hand grenade rigged to explode on the motorcycle.

His barrister, Sir John Nutting, QC, told the court that "it will be a long, long time, if ever, that [Cook] will rid himself of the fear of discovery". So, fearing the consequences of being dropped from the programme, he decided to challenge Scotland Yard. A leading human rights lawyer and barrister threatened judicially to review the Met's decision to withdraw protection. When Cook's team was granted leave to appeal, Scotland Yard's lawyers backed down and agreed to reinstate him under a new contract.

Had the case gone to court, it could have proved a major embarrassment for the Met and the Government's new crime-busting organisation, the Serious and Organised Crime Agency (Soca). Not only would all the past scandals of police corruption and supergrass mismanagement be rehearsed, but also, perhaps more crucially, the hearing would have attracted unwelcome publicity at a time when the security establishment was controversially trying to rehabilitate the supergrass as a key weapon in its "war on terror" and sell the "programme" to radicalised British Muslims.

Cook continues to live as someone else. He says he has turned his back on crime for ever. It is unlikely that the London underworld has turned its back on him.