When Diana, Princess of Wales, consulted the Queen for advise on their marriage, she was assured that the Prince of Wales “is hopeless”

In a new Channel 4 documentary, the Prince and Princess of Wales’ marriage problems and sex life are exposed, based on taped sessions between Diana and her voice coach.

In the recordings, the Princess’s voice coach, Peter Settelen, she alleges that Prince Philip urged Charles to give his marriage five years and then return to his lover, Camilla Parker Bowles, if it didn’t work out.

“My father-in-law said to my husband, ‘If your marriage doesn’t work out, you can always go back to her after five years’, which is exactly, I mean, for real I know that had happened after five years.

“I knew something was happening before that but the fifth year I had confirmation.”

Diana recalls during her meetings with Settelen that she confronted Charles about why Camilla Parker Bowles, now the Duchess of Cornwall, was in his life.

Diana said: ‘I remember saying to my husband, ”Why? Why have you got this lady around?” And he said, ”Well, I refuse to be the Prince of Wales who never had a mistress.”

The footage was shot between the end of 1992 and the middle of 1993, during the height of the so-called War of the Waleses.

Diana explained how she sought counsel from the Queen, or “the top lady” as she referred to her, and she was obviously displeased with the response on the film as she narrated the story.

She revealed: “So I went to the top lady, sobbing and I said, ”What do I do? I’m coming to you, what do I do?”

“And she said, ”I don’t know what you should do, Charles is hopeless”. And that was it, that was help.’

Diana also talks about how she met Charles, revealing that they barely spent 13 days together before being married.

And she was taken aback when he became romantic with her when they were lamenting Earl Mountbatten’s death.

“We were at a barbecue that night talking about Mountbatten and his girlfriend and I said, ‘You must be so lonely.’

“I said, ‘It’s pathetic watching you walking up the aisle with Lord Mountbatten’s coffin in front, ghastly. You need someone beside you…’

“Agggh. Wrong word! Whereupon he leapt upon me and started kissing me and everything and [waves arms] urrgh… You know, this is not what people do.”

‘Next day he said, ”You must come to Buckingham Palace with me, I have some work to do but you wouldn’t mind sitting while I do my work.”

‘I thought, ”Well, bugger it, I do mind sitting there while you do your work,’ and I said that and it sort of lit up something in him, that someone answered back. So I was quite a challenge.’

She added: ‘He wasn’t consistent with his courting abilities.

‘He’d ring me every day for a week, then wouldn’t speak to me for three weeks. Very odd. I thought, ”Fine. Well, he knows where I am if he wants me.”

‘The thrill when he used to ring up was so immense and intense. It would drive the other three girls in my flat crazy.’

Despite the fact that Mr Settelen was hired as a voice teacher, their £50 sessions in Diana’s Kensington Palace sitting room evolved into mock interviews, with the Princess answering extremely personal questions on camera.

Princess Diana also said she had intercourse with her husband Charles “once every three weeks” but it ended six or seven years before the recordings were produced, around the time Prince Harry was born in 1984.

She also described being with the Royal Family at Balmoral when she began dating Charles as “being sucked in.”

She admitted to finding solace with her married police protection officer Barry Mannakee, a connection she claimed was not sexual, but she admits in the tapes that she pondered quitting the Royal Household to be with him.