Senior Tory cabinet ministers were supplied with underage boys for sex parties, it is sensationally claimed.
Former Conservative activist Anthony Gilberthorpe said he told Margaret Thatcher 25 years ago about what he had witnessed and gave her names of those involved.
His allegations that he saw top Tories having sex with boys comes after David Cameron launched a Government inquiry into claims of a cover-up.
Anthony, 52, said: "I am prepared to speak to the inquiry. I believe I am a key witness."
Trawling seedy streets during a Tory conference, Gilberthorpe says he was asked to find underage rent boys for a private sex party at a top hotel.
Today, more than three decades later, he claims he was acting on the orders of some of the most senior figures of Margaret Thatcher's government.