The dozens of missing Home Office files relating to alleged sexual abuse "were probably destroyed", the department's leading civil servant told MPs today.
Mark Sedwill said he was "concerned" about the 114 files that the investigation he commissioned last year was unable to locate.
"They cannot be confirmed to be destroyed because there is not a proper log of what was destroyed and what wasn't," he said.
Mr Sedwill said that he "presumed that we would be able to locate" the Dickens dossier, "so of course it is a matter of concern to me that we no longer have copies of that correspondence".
"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."
The Baroness says she did not consider the "difficulties" caused by her background and family connections to the child sex abuse inquiry.
Questions have been raised of former High Court judge Baroness Butler-Sloss since her appointment last week.
22 police officers are now assigned to Operation Fernbridge - the probe into claims of a Westminster cover-up of sex child abuse.