Campaigning MP Simon Danczuk, who helped reveal child sex abuse by former Liberal MP Cyril Smith, has called for an over-arching inquiry to investigate all allegations of historic abuse.

And he called on former Tory home secretary Sir Leon Brittan to "step forward" and explain how he handled allegations about such cases which were presented to him in a dossier by former MP Geoffrey Dickens in the mid-1980s.

There were claims in the dossier about a network of paedophiles linked to the notorious Paedophile Information Exchange "working in and around Westminster" at the time, he said.

And he claimed politics was "the last refuge of child sex abuse deniers" where claims were swept under the carpet and pressure applied on people not to name names.

Danczuk, who has written a book about the Cyril Smith scandal, was giving evidence to the home affairs committee of MPs and had previously said he was ready to name a living politician who he believes is guilty of child abuse.

However the question was not put directly to him. But, when asked by committee members what he wanted to see done now to tackle the historic abuse claims he called for a full inquiry.

He specifically referred to the campaign by Dickens, who died in 1995, who investigated PIE and claimed there was a paedophile network involving powerful, senior figures in positions of responsibility.

Danczuk referred to the dossier Dickens was known to have presented to Brittan at the time about PIE and "paedophiles operating and networking in and around Westminster."

"It would be helpful if he (Lord Brittan) stepped forward and shared his thoughts on where that dossier is...and to share his knowledge of how he dealt with these allegations that were made at the time," he said.

The whereabouts of the dossier was not now known and the inquiry he wanted to see created should look at that issue and Brittan and others could then share their knowledge about what was going on at the time, he said.

Danczuk also told the MPs he believed institutions such as the police and local councils had changed their attitude to child sex abuse but politicians had not.

"Politics is the last refuge of child sex abuse deniers. The police dealt with this and changed the culture, local authorities are beginning to change the way they deal with it, the media are keen to investigate it.

"But in terms of politics there is a continual view that we should sweep it under the carpet, that we should not speak about it, that we shouldn't name people, that there should not be a discussion about what has gone on in terms of child sex abuse, and pressure is applied to people," he said.

And, when questioned, he said pressure had been applied to him not to name people.