Margaret Thatcher told officials not to publicly name a senior diplomat connected to a paedophile scandal despite being fully briefed on allegations made against him, a newly revealed secret file has shown. The file was prepared for the late Conservative Prime Minister in the early Eighties, and details allegations of unnatural" sexual activity by Sir Peter Hayman in 1966, when he returned from ... West Berlin to the Foreign Office. It also notified Mrs Thatcher that the senior diplomat had been subject to a police investigation, after a parcel containing "obscene materials" was found on a London bus in 1978. Sir Peter was not prosecuted following an investigation into his activities. The diplomat, who died in 1992, was accused of being a paedophile by MP Geoffrey Dickens under the cloak of parliamentary privilege in 1983, before the file was prepared for the then Prime Minister. Compiled between October 1980 and March 1981, the 37-page file is now available for public view, and features Mrs Thatcher's handwritten annotations and notes. It confirms that Sir Peter was a member of the Paedophile Information Exchange (PIE) group, and claims he intended to make "contact with adults with whom he could exchange obscene material." The revelations come as Home Secretary Theresa May announced she would be launching an inquiry into historical child abuse, during which Sir Peter's activities will be investigated.