Leon Brittan is named in secret files following historical sex abuse review

Peter Morrison, who was an aide to Margaret Thatcher, ex-diplomat Sir Peter Hayman and former minister William van Straubenzee are also mentioned in the documents released by the Home Office.

One of the files relating to Hayman was held by the Cabinet Office but “overlooked” during a previous trawl for information.

Documents that refer to Straubenzee had been earmarked for destruction but National Archives officials flagged them up to the Government.

A group of papers that name Morrison, Brittan, Hayman and Straubenzee as well as contain references to the Kincora children’s home in Northern Ireland where boys were abused were “found in a separate Cabinet Office store of assorted and unstructured papers”.

The admission came after MPs left Westminster for the summer recess. In a document published on the Government’s website, the Home Office said a fresh search of the archives had been carried out after a file emerged earlier this year that should have been submitted to the Wanless and Whittam inquiry into the handling of allegations that prominent figures were child abusers.

Peter Wanless, head of the NSPCC, and Richard Whittam QC, reported last year that they had found no evidence that records were deliberately removed or destroyed.

After examining the latest batch of documents, they said they “found nothing to cause us to alter the conclusions drawn or recommendations made in our review”.

But they warned that the emergence of papers after the review had been completed was not “helpful” in giving the public confidence in the process.

The investigators also revealed that allegations about an MP with a “penchant for small boys” were dismissed on the basis of his word with the potential political fallout the top priority rather than the risk to children.

Mr Wanless and Mr Whittam said the latest discovery, which came to light earlier this year, showed the need for a broader search of documents “unconstrained by what the Home Office in particular might or might not have known”.