Former Home Secretary Leon Brittan is reported to have been interviewed by police over a historical allegation of rape.
The Independent on Sunday says Lord Brittan, as he is now known, is understood to have been questioned last month about the claim, which relates to an incident in London in 1967.
The Tory peer reportedly strongly denies the allegations.
Lord Brittan, 74, was not an MP at the time of the alleged rape.
In a statement, Scotland Yard said in late 2012 a woman claimed to police that she was raped by a man at an address in the capital.
It said the woman was over 18 at the time of the incident.
Police added that a man in his 70s was interviewed under caution, by appointment, at a central London location last month. He was not arrested and inquiries continue.
The BBC understands that man was Lord Brittan, who was home secretary in Margaret Thatcher's Conservative government from 1983 to 1985.
Lord Brittan, who was first elected as an MP in 1974, later became Trade and Industry Secretary. He stood down from the Commons when he became a European commissioner in 1989.
Downing Street sources said they did not know about the questioning.