A UK academic has uncovered a file which he claims could contain allegations of “unnatural” sexual activities against public figures at the height of the Westminster child abuse scandal.

Dr Chris Murphy, a security and intelligence lecturer at the University of Salford, found the classified document while searching the National Archives in Kew.

While its contents have not been made public, Dr Murphy said he was immediately alerted by the title showing it had been taken to the then-Prime Minister, Margaret Thatcher.

The title read: “PREM19/588 – SECURITY. Allegations against former public [word missing] of unnatural sexual proclivities; security aspects 1980 Oct 27 - 1981 Mar 20.”

According to Sky News, the Cabinet Office has been made aware of the file and it will be made available to the ongoing panel inquiry into the alleged existence of a paedophile ring involving senior Westminster figures.

In pictures: White Flowers Campaign to support child abuse victims Show all 10 1 /10 In pictures: White Flowers Campaign to support child abuse victims In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign A campaigner holds a banner at Old Palace Yard in Westminster, during an event organised by the White Flowers Campaign Group, in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Pictures, messages and floral tributes left at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Jenny Tomlin, the mother of Martine McCutcheon, attends a gathering at Old Palace Yard in Westminster, organised by the White Flowers Campaign Group, to lay white flowers in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Child abuse campaigner Bill Maloney speaks to relatives, supporters, victims and survivors of abuse as they gather at Old Palace Yard in Westminster to lay white flowers in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Rotherham MP Sarah Champion speaks during a gathering at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group, to lay white flowers in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Simon Danczuk MP speaks during a gathering at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group, to lay white flowers in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign John Mann MP attends a gathering at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group, to lay white flowers in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign A woman leaves a floral tribute at Old Palace Yard in Westminster In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Relatives, supporters and survivors of abuse hold a minutes silence during a gathering at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group, in commemoration of victims and survivors of child abuse In pictures: White Flowers Campaign to support child abuse victims White Flowers Campaign Jenny Tomlin, the mother of Martine McCutcheon (left) supports Esther Grace of Cardiff, a victim and survivor of abuse, during a gathering at Old Palace Yard in Westminster, organised by the WhiteFlowers Campaign Group, to lay white flowers in commemoration of victims and survivors of child abuse

Dr Murphy told the broadcaster: “The fact that this file is concerning the Prime Minister and these allegations are being taken to the Prime Minister I think would strike anybody of being potentially of some interest.”

The embattled inquiry was set up by Theresa May, the Home Secretary, to find out whether public bodies had neglected or covered up allegations of child sex abuse in the wake of claims paedophiles had operated in Westminster in the 1980s.

Two chairs of the inquiry, Lady Butler-Sloss and Fiona Woolf, have already stood down over concerns over their links to the public bodies being investigated.