LONDON — The chief civil servant at Britain’s Home Office has pledged to engage a senior lawyer to review the handling of child sex abuse allegations against senior public figures three decades ago.

Mark Sedwill, permanent secretary at the Home Office, said in a letter to Keith Vaz, chairman of Parliament’s Home Affairs Committee, that an independent investigator had found 114 potentially relevant files on the matter were “presumed destroyed, missing or not found.”

Sedwill also wrote to Prime Minister David Cameron saying that he’ll appoint a lawyer to further probe the issue in the next week.

The Home Office investigations underscore how an appetite for historic scrutiny of sexual offenses that has already rocked the U.K.’s entertainment industry is now gripping the political establishment. A series of legal cases involving celebrities culminated most recently in the jailing last week of Rolf Harris, the 84-year-old Australian-born ex-host of British Broadcasting Corp. television shows.

“We need to be very open about these things,” Francis Maude, minister for the Cabinet Office, told Sky News today. “There can’t be any hint of a cover-up and I know that’s how this will continue to be approached.”

Sedwill commissioned an investigation in February last year after a query from Labor lawmaker Tom Watson, appointing an “experienced investigator” from Britain’s tax authority, HM Revenue and Customs.

“I asked the investigator to review all relevant papers received by the department concerning organized child sex abuse and whether the appropriate action was taken throughout the period 1979-99,” he wrote in his letter to Vaz. Sedwill commissioned the new review “to be reassured that the conclusions of the investigation remain valid.”

Vaz told the BBC today that it was “a huge surprise” that files which may be linked to historic abuse claims had been lost “on an industrial scale.” He said he’d asked Sedwill to appear before his parliamentary committee on July 8.

Part of the investigation last year centered on a dossier presented in 1983 by now-deceased Conservative lawmaker Geoffrey Dickens to Leon Brittan, who was the Home Secretary at the time. While the probe couldn’t locate that file, it did find correspondence from Brittan to Dickens saying that his allegations had been considered and some had been referred to “the proper authorities,” Sedwill said.

Aside from making a tally of 114 unavailable files, the investigation also identified 13 “items of information” about alleged child abuse, Sedwill said. Nine had been reported to police including four cases involving Home Office staff. Four previously unknown items have now been passed to police.

Asked on the BBC’s Andrew Marr show whether there could have been a cover-up by the political establishment in the 1980s, Norman Tebbit, a cabinet minister in Margaret Thatcher’s government, said “there may well have been.”

Labor lawmaker Margaret Hodge told Sky News that there has been a “veil of secrecy” over the establishment.

“Thank God it is coming out into the open,” Hodge said. “Now the establishment, who thought they were always protected, find actually they are subject to the same rigors of the law and that’s right.”

The police investigations into historic child abuse “are ongoing,” Sedwill told Vaz. “The Home Office will continue to cooperate fully with them and provide any material they seek or that we consider might be useful or relevant to them.”