Police raid Harry Roberts's cell in inquiry over leaked documents

Police have raided the cell of the notorious police killer, Harry Roberts, as part of an inquiry ordered by the Home Office into how secret documents were leaked to the multiple murderer.

Confidential letters and statements containing damaging and sensitive allegations against Roberts, 71, were sent to him in jail.

Several of the people who made the allegations against Roberts are understood to be considering legal action against the Government, and have claimed their safety is now under threat because of the unlawful disclosure. The Home Office ordered a police inquiry into the leak earlier this summer.

Roberts is seeking parole after spending 40 years behind bars for the murder of three unarmed, plainclothes officers in Shepherd's Bush, West London, in 1966.

At the Old Bailey, the trial judge described the murders as "the most heinous crime for a generation or more" and told Roberts he would serve at least 30 years.

Despite serving 10 years more than his 30 year tariff Roberts has been refused parole following a series of undisclosed allegations that he carried out illegal activities while on day releases.

The Home Office made unprecedented use of anti-terrorist laws to ensure the allegations remained secret, despite repeated legal challenges by Roberts' lawyers. The Parole Board argued that sources would be at risk if Roberts was allowed to view the evidence.

But, earlier this year, the confidential parole documents were leaked and distributed to a number of people, including to Roberts at the low security Category C prison at Littlehey in Huntingdon, Cambridgeshire.

Prison officers at Littlehey HMP told Roberts in June, that although he could not keep the documents, he was permitted to look at them several hours a day. A large number of the documents were also photocopied for Roberts at the prison and sent to his solicitor, Simon Creighton.

Mr Creighton, a partner in the firm Bhatt Murphy, having obtained permission from the Parole Board and Ministry of Justice, was then able to read for the first time some of the allegations made against his client. That resulted in the case being referred back to the Parole Board for consideration.

Once news of the disclosure reached the Attorney General's Office, Derbyshire Police were ordered to investigate the source of the leak by the Home Secretary. The documents, contained on a computer disc, were held by a number of organisations including the Parole Board, the police, the Home Office, and the Court of Appeal.

As part of the leaks inquiry, detectives from Derbyshire Police raided Roberts' prison cell and removed all his papers and documents at the beginning of August. They also arrested the man alleged to have sent them to Roberts at the prison and seized documents, and a computer from his home. The Treasury Solicitor has obtained a gagging order prohibiting the media from publishing any details contained in the letters and statements.

The Government and its legal advisers are due to decide later this year whether the secret material should be officially disclosed to Roberts as part of his new parole review.

Home Office lawyers, the Treasury solicitor, and ministers from the Justice department are expected to consider three options: to make public the papers; to keep some of the material restricted, but allow Roberts' lawyers to see it; or to refuse disclosure and have a special advocate re-examine the case.

Mr Creighton said: "The case demonstrates quite how dangerous it is to rely on secret evidence. The underlying principle for everyone, is a right to know the case against them. This is essential to achieve justice."

But some of the people who have made the allegations against Roberts are understood to be considering taking legal action to try and prevent the public disclosure of the information.