By Tom Parmenter, Sky News Correspondent
The Government's refusal to reveal the titles of four files related to child abuse has been branded "disgusting" by the family of a boy missing since 1979.
It is now over a month since the Cabinet Office confirmed it had found four more files relevant to the ongoing child abuse inquiries centred on VIPs in Westminster.
Officials have promised the files will be handed over to the police and various inquiries but they are still refusing to allow the titles of the files to be made public, let alone the contents.
At the start of February Cabinet Office minister Francis Maude said: "Officials have identified four additional relevant files, one of which was marked for destruction."
Despite repeated requests from Sky News over the course of the last month officials at the Government department say their position remains unchanged.
It has angered many survivors and campaigners, not least the family of Martin Allen who was 15 years old when he vanished in London nearly 35 years ago.
The teenager was last seen on the London Underground with an unidentified man at Gloucester Road station on 5 November 1979.
His brother Kevin Allen told Sky News he was "pretty definite" there is a link between the establishment abuse networks in Westminster and his brother's disappearance.
He said he could not accept that the names of the files are still being withheld.
"It makes me very angry, because these people have got a hold over us.
"It is our information, these people are our employees taking our money which is more than 'Mr Average' earns probably in the course of a month. It is disgusting.
"It is our lives they are playing with. I hope they can sleep at night."
Mr Allen is in regular contact with Met police detectives leading abuse inquiries which include allegations boys were killed.
While the content of the files may be sensitive, refusing to reveal the names means the public has no way of tracking them or knowing how they are being dealt with.
It follows a Sky News investigation which unearthed another classified file in January that the Cabinet Office had kept closed on grounds of national security.
After MPs raised the issue in the House of Commons, government officials were forced to release it to the National Archives.
The documents revealed former British diplomat, the late Sir Peter Hayman, was the subject of the secret file. The papers documented his "unnatural" sexual behaviour and his activities within the Paedophile Information Exchange group.
Neither the Hayman file nor the four new files were found during an earlier Home Office-commissioned search for documents relevant to ongoing abuse inquiries.
The Cabinet Office declined to make Mr Maude available for interview.
