Eighteen years after his death, however, the backbencher’s reputation as a political lightweight is being revised in the wake of a Scotland Yard investigation which is exhuming a scandal long buried in the Westminster of Margaret Thatcher’s premiership.

New evidence suggests that Dickens stumbled upon an Establishment paedophile ring in the early 1980s – and that his efforts to expose a cover-up left him in fear of his life. Dickens told fellow MPs that after warning of the existence of the network, he had received threatening phone calls and been burgled twice. He also claimed he had been placed on a “hit-list”, he told the House of Commons in a little-noticed speech.

For four years between 1981 and 1985, Dickens railed in Parliament against a paedophile ring which he claimed was connected to a trade in child pornography, then controlled by gangsters.

In 1981 Dickens had used Parliamentary privilege to name a diplomat and MI6 operative, Sir Peter Hayman as a pederast and demanded the Attorney General explain why he had escaped prosecution over the discovery of violent pornography on a London bus two years previously.

Two years later, in 1983, he warned a paedophile network involved “big, big names – people in positions of power, influence and responsibility” and threatened to expose them in Parliament.

In 1984, he campaigned for the outlawing of Sir Peter’s Paedophile Information Exchange (PIE) organisation. He also handed a dossier containing allegations of abuse of children in local authority care to the then Home Secretary, Leon Brittan.

After a 30-minute meeting with Sir Leon, Dickens said he had been “encouraged” but later expressed concern that the Cabinet Minister had not banned the PIE.

Last month Metropolitan Police began Operation Fernbridge into allegations that residents of a childrens home in Richmond, west London, were taken to the nearby Elm Guest House in Barnes, where they were abused.  Pornography involving adults having sex with children was allegedly shot at the property and then circulated commercially.

Sir Peter was among the visitors to the property. Others, according to a list seized by Scotland Yard last month, were the late Liberal MP Cyril Smith, the former Russian spy Sir Anthony Blunt, a Sinn Fein politician, a Labour MP, and several Conservative politicians.

After neighbours complained about the arrival of children, the police raided the guesthouse in 1982 but the operation was mysteriously cut short. A 2003 investigation also failed.

During a debate on child abuse in the House of Commons on 29 November 1985, Dickens warned that paedophiles were “evil and dangerous,” adding child pornography generated “vast sums.”

He went on: “The noose around my neck grew tighter after I named a former high-flying British diplomat on the Floor of the House.

“Honourable Members will understand that where big money is involved and as important names came into my possession so the threats began.

“First, I received threatening telephone calls followed by two burglaries at my London home. Then, more seriously, my name appeared on a multi-killer’s hit list.”

The Independent can find no corroboration for Dickens’ comments.

However twenty-eight years after he made them, Scotland Yard officers kept their new investigation secret for weeks, fearful that it would be closed down like earlier inquiries.

In a blog on his website, the Labour MP Tom Watson – whose claims of  a powerful paedophile network prompted the new inquiry – said that he had been advised by childcare  experts who have tried to expose the scandal to be careful about his personal security. He has asked the Home Office for the dossier presented by Dickens to Sir Leon, but it has not yet been found.

Dickens does not appear to have raised the issue in the Commons again prior to his death in 1995. He told friends he was surprised he had never been made a minister.

The MP: a man of verve

Geoffrey Dickens was one of the most colourful characters in the Commons during the 1980s and 1990s. Born in London in 1931, he was raised in foster care until he was eight.

He suffered polio at the age of 13 but recovered to become a heavyweight boxer. Mr Dickens was elected MP for Huddersfield West in 1979 and for Littleborough and Saddleworth in 1983, which he represented until his death in 1995.