Princess Diana was on holiday with her sons in the south of France when she discovered a heartbreaking tragedy.

The People's Princess had to consider a wide range of issues when going away with Princes William and Harry.

Having given up her royal protection officers after divorcing Prince Charles, Diana had limited options with where to take her sons during the summer of 1997.

"Diana's biggest problem after the separation from Prince Charles was what to do with the boys during the summer. Where to take them. What to do," says author Andrew Morton in Channel 5 documentary Diana: Her Last Summer.

Help came from an unexpected quarter when Mohamed Al-Fayed, who was very friendly with the royal family at the time, offered to provide the security and protection they needed.

Diana was granted permission by the Queen to take William and Harry to Al-Fayed's holiday home and yacht in St. Tropez.

Princess Diana and Prince Harry having fun on their holiday in St. Tropez

"They were swimming a lot together. They were going on the jet skis. They went off on the yacht somewhere for the day. They had a fun time," explains royal photographer Arthur Edwards.

"It was the life thee rich and famous live and she was getting some of it."

Diana became increasingly incensed with press intrusion into their holiday - with some people questioning her choice of host.

"The irony is William has since remarked that that time in the south of France was the worst week's holiday of his life," says Andrew Morton.

There was added public interest as Diana started growing close with Al-Fayed's son, Dodi, who left his fiancee Kelly Fisher on his yacht to go to his father's vessel.

Prince William would later call it 'the worst week's holiday of his life', according to Andrew Morton

Dodi left his supermodel fiancee high and dry, while images of him and Diana appeared all over the world.

Back in London, Diana's former butler, Paul Burrell, faced questions about her tangled love life.

While on the outside it looked like Diana was flourishing, she was dealing with inner turmoil amid a relationship with heart surgeon Hasnat Khan that had fallen apart.

Burrell says: "Every time Diana rang me she would ask about Haznat: 'Have you seen him? Have you been to his pub? Has he seen the pictures in the papers? What did he think? Is he jealous?

"Haznat was furious that Diana could turn to someone like Dodi, the son on a millionaire and a playboy, that wasn't Diana. He knew that wasn't his Diana."

Diana spent much of the summer with Dodi Al-Fayed

In the middle of all this, Diana received some devastating news that would bring the holiday to an abrupt end.

On July 15, Diana discovered that her close personal friend, Gianni Versace, had been brutally murdered in cold blood on the steps of his home in Miami Beach, Florida.

The Italian fashion designer was shot dead by Andrew Cunanan - and was just 50 years old and at the top of his game when his life was tragically cut short.

Diana was a close personal friend with the designer, having famously posed on the cover of Harper's Bazaar in a stunning Atelier Versace gown.

Five days later, grieving Diana made an agonising decision over William and Harry.

Diana decided it was best for William and Harry to be with their father in Balmoral

She decided it was best to cut the holiday short and take her sons back to the UK to be with their father.

William and Harry went to stay with Charles in Balmoral for the next month - after their last ever holiday with their mother.

The following day, Diana flew from London to Milan for Versace's emotional memorial service, sitting in the front row between tearful Elton John and Sting.

Devastated Diana was very shaken by the death of Versace and began to fear the same terrible fate might befall her.

Diana was a very close personal friend of Versace

"It deeply moved her. This was only months before she died herself," explains Burrell.

"Here she was sat at Gianni's funeral. She couldn't quite comprehend it.

"Death seemed to haunt her towards the end of her life. She was so consumed by thinking it might happen to her."

The next time that many of Diana's celebrity friends would be together again was at her own funeral just seven weeks later.

On her return to the UK, Diana met up with Khan for the final time and they ended their relationship forever after a "screaming match" in Battersea Park.

Diana was sat next to Elton John at Versace's memorial

Within 24 hours, she flew to Sardinia to Al Fayed's yacht to resume her romance with Dodi, where they were caught in a compromising clinch in photos.

After coming back to London she went to Bosnia to highlight the country's plight on a humanitarian trip.

She then briefly returned to London before going on a week-long Greek island cruise with a female friend.

On the day she came back to the UK she had lunch with William in Kensington, which sadly would be the very last time they would ever see each other.

Diana then flew back to the south of France with Dodi for their third and final trip on his father's yacht of the summer.

Diana have a very close bond with her sons

With Dodi having to go to Paris to do work for his father, Diana decided to extend her holiday by an extra day so she could fly home on his private jet.

According to Burrell, Diana spoke about seeing her sons in a heartbreaking final phone call.

She said: "Ring Balmoral. Tell the boys mummy will be with them 24 hours later than expected but to be there."

On August 31, Diana and Dodi would tragically both die in a horrific car crash in Paris.

"The roll of the dice in the last few hours of the Princess' life was just so unfortunate," says Burrell.

"Everything worked against her. Nothing was in her favour. She was in the wrong place at the wrong time with the wrong man."

CCTV footage of Princess Diana and Dodi Al-Fayed in the hotel lift was shown to the jury at the inquest into her death

The car they were travelling in back from a hotel crashed in a road tunnel, with Dodi and driver Henri Paul pronounced dead at the scene.

Bodyguard Trevor Rees-Jones survived, but Diana's injuries were too severe and she was pronounced dead at the hospital.

Emotional Burrell says: "She was alone she shouldn't have been there alone. I still curse her to this day for going all that way by herself and not having someone with you."

Prince Charles and Burrell flew to Paris to bring Diana home - with her ex-husband deciding to see her body.

"When he came out he was white. He was literally shaken. I had never seen him like that before," explains Burrell.

"I'd never seen him show so much emotion before. He suddenly realised the enormity of what had happened."

Princes William and Harry at their mother's funeral

Diana's death caused an unprecedented outpouring of grief around the world, with her funeral watched by an estimated 2.5 billion people

Mourners lined the streets of the UK to to pay their respects and left huge bundles of flowers outside Kensington Palace.

Then Prime Minister Tony Blair said she would always remain 'The People's Princess', while his former spin doctor Alistair Campbell revealed a private conversation they had.

Campbell says: "He said this is going to produce grief on a scale we've never seen. I said: 'Is that right?'.

"I got picked up by a car. It was a woman driver who was crying. This was the moment I thought this might be much bigger than anyone could ever imagine."

*Diana: Her Last Summer is available to watch on My5