Then-head of FBI sent cable to US embassy in London claiming he had been told Prince had links to Christine Keeler and Mandy Rice-Davies.

J Edgar Hoover sensationally suggested that Prince Philip may have been “involved” with the two women at the heart of the Profumo sex scandal.

Hoover, the then-head of the FBI, sent a cable to the US embassy in London claiming he had been told that the Prince had links to both Christine Keeler and Mandy Rice-Davies.

The cable, which was sent more than 60 years ago and has since been languishing in US Department of Justice archives, has been made available after a long-running Freedom of Information request.

It contains a claim made by Thomas Corbally, an American businessman working in the industrial espionage sector, who was friends with Stephen Ward, the fixer at the heart of the scandal.

Ward, an osteopath, had introduced Keeler, a 19-year-old model, to John Profumo, the secretary of state for war. Profumo was subsequently forced to resign over their affair, and the scandal threatened to bring down Harold Macmillan’s government.

John Profumo, the former war minister, was forced to resign

In the cable, obtained by the Mail on Sunday, Hoover wrote: “Corbally also stated there was a rumour Prince Philip may have been involved with these two girls.”

The diplomatic cable, sent by Hoover on June 20 1963, has fuelled speculation that had already been whipped up by The Crown, the controversial Netflix series detailing Elizabeth II’s reign.

In the Netflix show, Anthony Blunt, who was later outed as a Soviet spy, warns the Duke of Edinburgh that he will expose him over his relationship with Ward in response to the Duke threatening to expose Blunt’s treachery. The series has been dismissed as far-fetched and scurrilous, but has proved hugely popular.

The diplomatic cable, sent by Hoover on June 20 1963, has fuelled speculation that had already been whipped up by The Crown

The suggestion that Hoover was even linking Prince Philip to Keeler and Rice-Davies, both showgirls, will cause discomfort on both sides of the Atlantic.

For decades, Hoover was one of the most powerful men in the US, running the FBI and its predecessor for almost 50 years until he died in 1972, and conducting campaigns against suspected subversives and radicals.

After his death, he was accused of abusing his power, collecting evidence against powerful figures using illegal surveillance and wire-tapping.

J Edgar Hoover, the director of the FBI from 1924-1972, claimed that Corbally stated rumours about Prince Philip’s involvement in a cable memo

The prospect of Prince Philip, who died aged 99 in 2021, being even indirectly caught up in one of Hoover’s operations would have severely harmed Anglo-US relations at the height of the Cold War. It has previously been reported that he was an acquaintance of Ward, amid claims they were both members of a London club.

It was claimed that Blunt, who was the Surveyor of the Queen’s Pictures, was involved in purchasing every sketch of members of the Royal family produced by Ward, a keen amateur artist, when they went on display in a London gallery.

Ward was arrested and charged with living off the earnings of prostitution. He took an overdose of sleeping pills during his trial, was convicted in absentia and died prior to sentencing.

Keeler was introduced to Profumo by Ward at a party at the Cliveden estate in 1961, but was also having an affair with Yevgeny Ivanov, a Soviet spy and naval attache at the Soviet embassy in London.

Profumo’s career could not survive the extraordinary revelations that engulfed the then-Conservative government.