Westminster child sex abuse claims: What we know

Theresa May is expected to announce a review into claims of historic child abuse in the Commons later today. Credit: PA

The Government is coming under pressure to launch a "Hillsborough-style" public inquiry into allegations that some MPs in the 1980s were involved in the sexual abuse of children - and that a high-level conspiracy then saw their alleged crimes covered-up.

Read: Theresa May to order independent sex abuse claims investigation

Here are some of the key figures and facts in the case:

Simon Danczuk

Labour MP Simon Danczuk called on Lord Brittan to spell out what he knew about the Geoffrey Dickens dossier. Credit: ITV News

Labour MP Simon Danczuk last Tuesday called for former home secretary Lord Brittan to spell out what he knew about about a dossier handed to him in 1983 by the late Conservative MP Geoffrey Dickens that contained allegations of a paedophile ring operating in Westminster.

Danczuk, who is also the author of a book revealing claims of sex abuse by the late Liberal Democrat MP Cyril Smith, told ITV News that other alleged victims have come forward since he raised the claims.

Geoffrey Dickens

The late MP Geoffrey Dickens handed a file containing allegations of child sex abuse at Westminster to then-home secretary Leon Brittan. Credit: ITV News

Campaigning Conservative MP Dickens handed his dossier of files to then-home secretary Leon Brittan alleging that political figures were involved in child sex abuse.

Mr Dickens, who died in 1995, said that the information contained in the dossier would “blow the lid off” society, his son told ITV News.

Barry Dickens also revealed that in the weeks after his father submitted the information to the Government, the family's home was twice "professionally" burgled.

The Home Office has admitted that it can't find 114 “potentially relevant files” relating to the scandal and they could have been destroyed.

Lord Brittan

Former home secretary Leon Brittan. Credit: PA

The day after Mr Danczuk challenged Lord Brittan to reveal what he knew, the Tory peer said that at the time he was handed the dossier he asked Home Office officials to report back to him if "action needed to be taken", but that he could not recall having been contacted by them.

However, an independent review that was commissioned by the Home Office last year included a letter Lord Brittan sent to Mr Dickens that showed this statement to be incorrect.

In it he wrote: "The view of the Director of Public Prosecutions is that two of the letters you forwarded could form the basis for inquiries by the police and they are now being passed to the appropriate authorities."

The Home Office responded publicly to clarify its position and Lord Brittan was forced to issue another statement clarifying his position.

"Whilst I could not recall what further action was taken 30 years ago, the information contained in this report shows that appropriate action and follow-up happened," he said.

Today he denied mishandling the documents and said that he welcomed an independent Home Office review into the matter.

What is PIE?

Paedophile Information Exchange (PIE) was a pro-paedophile group that launched in the 1974 and survived for 10 years, attempting during that time to gain mainstream acceptance.

The group is believed to have featured among the files that Mr Dickens submitted to the Home Office.

Allegations surfaced today that a leading member of the notorious group work worked at the Home Office as a contracter and stored the group's material on its premises to keep it safe from Police raids, the BBC reported.

In a 1986 book available in a restricted part of the British Library, former PIE chair Steven Adrian Smith wrote: "I had a furnished office completely to myself seven days a week on a rotating shift basis.

"Much of PIE's less sensitive file material was stored in locked cabinets there, where no police raid would ever have found them."

How is Elm Guest House involved?

The Edwardian property in Barnes which was once the site of Elm Guest House. Credit: ITV News

Elm Guest House house existed in Barnes, south-west London in the 1970s and 1980s.

In 1982 it was raided by police and its owners Haroon 'Harry Kasir and his wife Carole were convicted at the Old Bailey of running a brothel.

It is now part of an ongoing police investigation into allegations of sex abuse involving senior cabinet ministers and boys from nearby children's homes, who were allegedly taken there.

What's the Cyril Smith link?

Liberal Democrat Sir Cyril Smith died in 2010. Credit: PA

In November 2012, Greater Manchester Police said that the late politician Cyril Smith, Liberal MP for Rochdale from 1972-1992, should have been charged with physically and sexually abusing young boys.

Mr Danczuk, the current MP for the area, made the initial allegations during a statement in the Commons earlier that month. In January 2013, police confirmed that Cyril Smith had visited the Elm Guest House.