Questions have been raised about choice of a former High Court judge to oversee the Government's inquiry into allegations of an establishment cover-up of child sex abuse.
Baroness Butler-Sloss is to head an expansive probe into whether abuse by politicians and other powerful figures in institutions during the 1970s, 1980s and 1990s was swept under the carpet.
But Home Affairs Select Committee chairman Keith Vaz was among those expressing surprise at the selection, saying that while Lady Butler-Sloss is "distinguished" she is also a member of the House of Lords.
Meanwhile, the top mandarin at the Home Office has admitted he is "concerned" that more than a hundred files linked to allegations of paedophile activity in Westminster have gone missing from its stores.
Rumours of decades of organised child abuse among the ruling class have moved centre stage over the past week, after high-profile campaigns by Labour MPs Tom Watson and Simon Danczuk.
Home Secretary Theresa May attempted to take the initiative yesterday by announcing two separate inquiries - one broad Hillsborough-style investigation led by Lady Butler-Sloss, and another into the historic issues at her own department.
Downing Street said Mrs May and Lady Butler-Sloss - who sits as a cross bencher in the Upper House - would be announcing the wider probe's terms of reference and panel members "within days rather than weeks".
The Prime Minister's spokesman pointed out that the peer had been president of the High Court Family Division as well as chairing the inquiry into the 1987 Cleveland child sex abuse scandal.
"It is the very wide respect that her professional expertise as well as her personal integrity commands that makes her a very strong appointment for this role. It is the width and breadth of her experience that counts."
But Mr Vaz said he was "surprised that the Government has chosen a Member of the House of Lords no matter how distinguished to head the inquiry".
He said: "She is a member of Parliament and is very closely related to a former Lord Chancellor."
Giving evidence to Mr Vaz's committee, Home Office permanent secretary Mark Sedwill announced that Richard Whittam QC will join NSPCC chief Peter Wanless in looking at the departments handling of child abuse allegations.
Former home secretary Lord Brittan has flatly denied failing to deal with a dossier provided by ex-MP Geoffrey Dickens in 1983 properly, while a review carried out by a HMRC official last year found no evidence that relevant material was not passed to other authorities.
However, it also disclosed that the Dickens file appeared to have been destroyed - and Mr Sedwill has since revealed that 114 files deemed potentially relevant are missing.
"I am concerned frankly about the 114. I am concerned about all the material that we cannot find," Mr Sedwill said.
"Most of these files were probably destroyed, because the kind of topics that they covered would have been subject to the normal file destruction procedures that were in place at that time.
"They cannot be confirmed to be destroyed because there is not a proper log of what was destroyed and what wasn't."
Mr Sedwill went on: "I must admit I presumed that we would be able to locate it (the Dickens dossier)... I presumed we would be able to find that, to find the responses and just be able to present that material...
"So of course it is a matter of concern to me that we no longer have copies of that correspondence, the family regrettably no longer have copies of it, and therefore we are having to work from file references, files largely that refer to it and descriptions of what happened rather than the original source material."
Mr Sedwill said he decided to draft in an expert investigator to look into the Home Office's handling of paedophile allegations in February last year in response to questions from Labour MP Tom Watson.
He refused to name the official who led the probe.
He said he "shared" the executive summary and "broad conclusions" with Mrs May after the report was produced in June, but it was "not appropriate" for her or her advisers to see the full version.
Mr Sedwill said he did not recall telling Mrs May until several months later that the 114 files were missing.
"I shared with the Home Secretary the executive summary and broad conclusions. I told her what we were doing with the material. But... it would not be appropriate for her or indeed for anyone other than a small number of people not least sensitive personal information within the report.
"Indeed I did not see all of the accompanying material myself."
Mr Sedwill said people "should not assume that there is anything sinister" in the absence of the missing files.
"Most correspondence from this period was destroyed after two years. Of course, serious material of the kind we were referring to was handed on to the appropriate authorities, so it was not retained by the Home Office," he said.
The mandarin fielded a succession of questions about his department's filing system, and how the initial review had been able to deduce that 114 files were missing.
He insisted he did not know the detail of how the referencing worked, whether the probe had uncovered titles of missing documents, or whether checks had been carried out on whether adjacent documents had disappeared.
Mr Sedwill said the probe used a variety of search terms to trawl the total database of around three quarters of a million files.
"That identified a total number of files that were relevant or potentially relevant, 573 were still available to be inspected. In that search 114 were identified (as missing)," he said.
The department's filing system had been "devolved" at the time, and comprehensive records were not kept centrally.
Mr Vaz insisted the Home Office should provide the names of the 114 missing files by the end of the week.
"There is a feeling in the committee that the first review was not satisfactory, in this sense. It's not a question of good faith or your choice of investigator - though we don't know who that is - but there seems to be a number of items that still need to be chased up in respect of the first review," he said.
Asked whether political parties' whips offices should also provide information to the inquiry, Mr Sedwill said: "All bodies who may have information that may be relevant to criminal investigations or may be relevant to the Butler-Sloss inquiry should carry out the kind of exercise I carried out last year, with proper independent scrutiny, and provide that information."