Former prime minister Margaret Thatcher knew about politicians sexually abusing children, but failed to act against them, an MP has told Sky News.
Simon Danczuk, who exposed Sir Cyril Smith as a prolific child abuser, said: "There is no doubt about it now, from what we know, that she turned a blind eye to people who were quite clearly paedophiles. That is absolutely clear.
"It is a real stain on Margaret Thatcher's legacy and I don't get any pleasure from saying that, but she turned a blind eye to it."
The Rochdale MP also claimed the Government is refusing to publish at least four other files on historic child abuse because it was worried about what information may come out before May's General Election.
He added: "(The Cabinet Office) have resisted publishing these documents for over 12 months - that's not acceptable.
"They refused to tell the public who nominated Cyril Smith for a knighthood. A journalist managed to get that out of them after going to the Information Commissioner. It was indeed David Steel.
"And we now know they are resisting publishing at least four other files relating to historic child sexual abuse.
"We have to ask the question is the Cabinet Office fit for purpose?"
"The reality of it is, this is the truth of the matter, we are approaching the General Election. This isn't party political, but [the government parties] are concerned about what information is going to come out before the General Election, that's the truth of it.
The Cabinet Office has denied trying to cover up information about Downing Street's knowledge of Smith's abuse of young boys before he was knighted.
Documents show Mrs Thatcher was made aware of the claims about the Liberal MP before he was handed the honour in 1988.
The 19-page dossier of information on the decision to give Smith the knighthood contains several letters, including an undated one from a Political Honours Scrutiny Committee member to the then prime minister.
In the letter, marked secret, Lord Shackleton said police investigated Smith in 1970 for "indecent assault against teenage boys" between 1961 and 1966.
But, the letter noted, the Director of Public Prosecutions (DPP) decided "there was no reasonable prospect of conviction".
The letter to Mrs Thatcher said the case was reported in the Rochdale Alternative Press and Private Eye, adding: "One may regret this kind of press reporting but it could be revived if an award to Mr Smith were made."
Lord Shackleton also said it would be "slightly unfortunate" if this "episode" stopped Smith, who died aged 82 in 2010, receiving the knighthood.
But he added: "We felt it right to warn the honours system would be at some risk if the award were to be made and announced."
The documents were released to the Mail on Sunday following repeated demands for disclosure under the Freedom of Information Act since April last year.
The documents were only made public on Friday after an intervention by the Information Commissioner, the paper said.
Home Office Minister Lynne Featherstone told Sky's Murnaghan programme: "Those Cabinet files, in my view, should without doubt be published.
"We have to get to the bottom of this, high or low, it doesn't matter. Wherever we find it, we have to root out sexual abuse, child sexual abuse, child sexual exploitation."
A Cabinet Office spokesman said: "There is no cover-up nor was the Cabinet Office forced to release this information by the Information Commissioner.
"This is a sensitive and complex case and it is right that we considered advice from a range of officials. After considering the advice, the Cabinet Office decided to disclose information."