The argument has been going on for almost thirty years around the finest dinner tables across the country: Who broke their vows?

Did her husband’s infidelity cause Princess Diana, a lonely woman who was feeling vulnerable to find solace in another man’s arms? 

Perhaps Prince Charles was encouraged by the evidence that showed his wife cheating to resume his long-standing relationship with Camilla Parker Bowles.

Diana, herself, couldn’t be clearer during her famous Panorama interview, when she stated about her rival love: “Well, there was three of us, so it wasn’t too crowded.”

She said that her bulimia, and self-harm, are the results of the prince’s infidelity.

In recent years, this version has become so definitive that millions have viewed The Crown on Netflix. They were told by Charles that he was the first man to break up with his wife.

But yesterday an unexpected voice entered the fray — one the public have never heard from before — to offer an entirely different narrative. 

Fast 30 years ago, the dispute has continued around the tables of some the most prestigious dinner parties in the nation: Charles or Diana?

The Mail’s Richard Eden, the Mail’s diarist, revealed that Prince Charles’s ex-police bodyguard, Sergeant Allan Peters has spoken out in a shocking interview. He claims that Prince Charles only returned to Camilla after discovering Diana was having an affair with Barry Mannakee, a fellow protection officer.

Peters claims that he was the one who told his prince about his affair with his wife. Although claims about Mannakee and the princess, who was a father-of-2, died in an accident on a motorcycle in 1987, they have an interesting twist thanks to Peters.

It does not seem a good time to bring up this topic. Questions about Queen Elizabeth’s health are very high on public minds, as well as the simmering tensions that exist between Prince Harry (and the Royal Family).

Many speculate, therefore, that Charles is moving closer to the throne and that Sgt Peters may have even been encouraged to make an intervention. 

This argument suggests that it would not make sense for Charles, the prince, and Camilla, his wife, to be made the villain in the story about Diana’s marriage breakdown.

It was not him who broke the marriage vows first, but she.

A figure close to the princess said that it was quite extraordinary that Allan Peters (who has rarely spoken about his royal service) would choose to speak now and on this subject. It does raise questions about the motivation.

Others have also suggested that Peters might feel a little jealousy in his recollections. 

Since 1989 when Diana and he parted ways, the former policeman has not said a word publicly but CNN interviewed him to show that he still has much to say about Diana.

‘The popular perception is that the Prince of Wales was straying throughout his marriage — and that is definitely, unequivocally, not the case,’ the retired officer told the channel. 

The princess was the one who first strayed. After learning about Mannakee’s affair, he returned to Mrs Parker Bowles.

Diana's ex-police bodyguard Sergeant Allan Peters claimed Prince Charles returned to Camilla (both pictured) only after he discovered Diana had been having a fling with Barry Mannakee

 Diana’s ex-police bodyguard Sergeant Allan Peters claimed Prince Charles returned to Camilla (both pictured) only after he discovered Diana had been having a fling with Barry Mannakee

Peters, who spent seven years at Diana’s side in the 1980s until he was abruptly removed, says he began to notice the princess behaving oddly whenever Mannakee — who like him looked after Princes William and Harry as toddlers — was around.

He said that she initially denied any untoward happenings. “But she then told me what she meant. She was in a relationship with Mannakee.”

The prince then approached him to ask about his wife.

The officer responded: “You need to talk with her.”

Peters then stated that Charles said to Peters: “Well, she’s tried everything, but the only thing seeming to upset her is Barry Mannakee’s return to uniform. Barry could stay if she is so upset.

Astonishingly, Peters then said that if that happened, he would have to leave — presumably because he felt it would compromise his position. 

‘I think at that point the penny dropped — he was utterly shocked and was clearly very upset.’

The interview with the sergeant suggests that we might need to reevaluate the steps leading to the collapse of the Waleses’ marriage. Which party was the first to betray whom?

For years, rumors about Diana’s relationship to Mannakee were circulating.

When she learned of his death from Prince Charles — the couple were en route to the 1987 Cannes Film Festival — she wept uncontrollably, tearing at her clothes and scratching her arms and legs so much that on arrival her gown had to be adjusted by a lady in waiting to cover the damage to her body.

There were conspiracy theories about his death that, after the winks and nudges had ended. They suggested that he had been “bumped off” to keep his silence.

Another years passed and the Princess described Mannakee in tape recordings that were made by Peter Settelen, her voice coach. 

“I only felt happy when he was here.” [and]He was so kind to allow me to leave everything behind and go live with us. Can you believe it? He kept repeating that he believed it to be a great idea.

Diana could have really thought about leaving Charles for a better life? Her father, who had been a Ford worker at the Dagenham plant in Dagenham, was also a Ford employee. It seems impossible, even though it has been many years since.

He was married with his two children and arrived at Kensington Palace in 1986. The princess was 24 years old, he was 37. Along with her top protection officers Inspector Graham Smith, and Sergeant Peters, he worked in a rota.

His easy-going relationship with Diana was irritating to others from the very beginning. His closeness with Diana eventually led to a closeness which sometimes caused his colleagues to feel “quite uncomfortable”. 

A work colleague recalled that she could clearly see her liking him. It was Barry this, Barry that. It was Barry’s blabbermouth, and we didn’t believe there was any between them. He would have proudly boasted about it. He never did.’

Claims about the princess and Mannakee (both pictured), who died in a motorcycle accident in 1987, are not new but it is the Peters dimension which has given them an intriguing twist

While claims that the Princess and Mannakee died in a motorbike accident in 1987 are not new, they have an intriguing twist thanks to the Peters dimension.

It was an era of increasing turmoil for Princess Diana, and the stress of her unhappiness in marriage was growing. 

And Mannakee was not only a good talker, he was also a very good listener — particularly on their regular 90-minute drives taking the children to Highgrove for the weekend.

They called them their “M4 chats”. She would have him in her car as William was taken from Kensington Palace to Mrs Mynors Nursery School, Notting Hill. Diana would also call to get her son.

The relationship certainly annoyed Palace staff — the valets, butlers and dressers — because Diana was always asking his opinion about just about everything.

Whether this closeness developed into intimacy is not something Diana divulged on her video recordings — indeed, she never even mentioned his name beyond saying she had fallen ‘deeply in love with somebody who worked in this environment’.

However, it is a fact that princesses and cops are often alone in their circumstances. His presence was comforting to her, so it wasn’t surprising she began flirting with him. Mannakee, a confident woman, was not afraid to have a fling with Diana even though she wasn’t allowed by servants.

Once, she dressed for a dinner date and playfully wiggled her bottom —clad in a tight, short skirt — at him. “Do you think I’m looking all right?” He asked her. 

Mannakee’s response, according to observers, was: “Sensational, because you know that you do.” Mannakee then added, “I can quite imagine you.” Diana laughed and replied, “But you already have that,”

They were a perfect match. Soon, he was her designated protection officer for shopping trips. They were seen driving on empty roads together at Balmoral.

Mannakee’s easygoing nature with children was what made him so special to her. He played and laughed with them in a different way to Charles who needed to be coaxed to the nursery.

When she felt particularly low, Mannakee came to start his shift. Diana sobbed and threw her body into Mannakee’s arms. “I just cannot.”

Talk quickly broke about the situation throughout the Palace. It was not the same storm as the one that broke out on the evening of July 22 1986 (the night prior to Prince Andrew’s and Fergie’s wedding).

According to legend, Diana chose the gown she would wear at the Westminster Abbey wedding and then kissed her children goodbye before hurrying to her drawing area. Mannakee was waiting. 

A senior member of Charles’s team walked in and knocked on the door. According to reports, he found the officer comforting the princess by wrapping his arm around him.

Mannakee, who had served as royal protection officers for several hours, was quickly informed by the prince about what had happened and was promptly terminated. It wasn’t quite what Allan Peters remembers.

Peters, who spent seven years at Diana's side in the 1980s, says he began to notice the princess behaving oddly whenever Mannakee was around. Pictured: Diana and Charles in 1989

Peters was seven years with Diana in 1980s. He says that he noticed the Princess behaving strangely when Mannakee was nearby. Photograph of Diana and Charles 1989

Mannakee, who was accused of being too familiar, was summoned to his superiors. He was then put back into uniform and assigned diplomatic duties, rather than royal protection. Mannakee was then told that he was being transferred on his own initiative.

At the time, he told Mail: “I was transferred because of domestic reasons.” It meant working long hours far from home. According to him, Diana and he were “good friends”, nothing more.

Mannakee died a year later when his Suzuki motorcycle, on which he was riding as a pillion passenger, collided with another car. Ken Wharfe (who took over Mannakee’s duties as William and Harry’s bodyguard, before taking the place of Sgt Peters on Diana’s side) has not believed the gossip. Diana said to Ken Wharfe that the gossip was part of Prince Charles’s’smear program’ against her.

Wharfe said that Diana was open to lying, although she believed in the truth at times. Diana did not tell anyone, even her closest friends, that she had an affair. However, Wharfe said Mannakee had “meant an awful lot” to her, and that he was “my father figure, looked after me.”

Simone Simmons, Diana’s long-time friend, remembers Diana “swearing” on the lives of her children that there was no affair. 

She stated that she had spoken to him many times and could talk to him about her feelings. He also gave information to Camilla, which he found out.

Diana wasn’t certain who cheat first. It was clear to her that Charles hadn’t stopped seeing Camilla.

Allan Peters was also with the princess just before Prince William’s 1982 birth. He, too, had moved on, much like Mannakee.

Having twice leapt to the princess’s aide — once even reaching for his gun — he was reported to have annoyed Diana by ‘overstepping the mark’.

My mother put it better to me: He was too close with my husband’s family.

Diana asked me once to go with her to East London to visit a crematorium. To find it, we relied on an old battered A-to Z street map of London in those days before satnav.

Although I don’t know if Barry Mannakee was born on this date or if it was the anniversary of his passing, she did want to send flowers to his family.

He died many years ago, and his friend told her that she will always be grateful.