Prince Philip has been sensationally named in top-secret FBI documents about the Profumo affair in the early 1960s.

The late Duke of Edinburgh’s role in one of the most notorious scandals of the 20th century has long been a source of speculation until now.

According to a report by the Mail on Sunday, papers show that the FBI had been told Prince Philip was personally ‘involved’ with Christine Keeler and Mandy Rice-Davies, the two women at the centre of the sex scandal that brought down the British government.

US Department of Justice files show that a memo was written by J Edgar Hoover, then director of the FBI about the scandal highlighting that Prince Philip was involved.

At the heart of the scandal was the married secretary of state for war John Profumo, who had denied in the Commons in March 1963 that he had a sexual relationship with Keeler who was a teenage showgirl. He was forced to resign months later when proof of the affair became public.

The scandal had national security implications because Keeler was also meeting Russian military attaché Yevgeny Ivanov.

Well-connected osteopath Stephen Ward, who had introduced Keeler to Profumo at a party, was charged with living off the immoral earnings of Keeler and her friend Rice-Davies. He took a fatal overdose and died just three days after he was convicted.

Thomas Corbally, a US businessman involved in industrial espionage, who agreed to be interviewed by the FBI about his friendship with Ward, made the claim about Prince Philip who was also said to have seen Ward for appointments.

A cable sent by Hoover to the US embassy in London on June 20, 1963 reads: “Corbally also stated there was a rumour Prince Philip may have been involved with these two girls.”

Prince Philip’s links to the Profumo affair was a central storyline in the Netflix series The Crown.

Sir Anthony Blunt, the Queen’s curator of art who was later exposed as a Soviet spy, warned Prince Philip that he would expose his relationship with Ward when Philip tackled him over his treachery.

It was revealed that Philip had been in contact with Ward on a number of occasions and had even been sketched by the artist at Buckingham Palace.

Buckingham Palace has been approached for comment.