As the 25th anniversary of Princess Diana’s death is marked this week, her former bodyguard Ken Wharfe reflects upon her impact and legacy

Photo: Jayne Fincher/Getty Images

Twenty-five years after the death of Princess Diana, her legacy is felt most through her beloved sons, Prince William and Prince Harry.

When William congratulated England’s national women’s soccer team on the field at Wembley Stadium on July 31, he opted for hugs instead of the formal handshakes normally associated with his role as President of the Football Association.

“He was hugging the players and engaged in close conversation,” Princess Diana’s former bodyguard Ken Wharfe tells PEOPLE. “That was classic Diana.”

For Wharfe, who was the main police bodyguard looking after Princess Diana and her sons from 1987 to late 1993, the living legacy of Diana is in her sons William, 40, and Harry, 37.

Prince William. Jonathan Moscrop/Getty

The brothers adopted her unique way of engaging with the public — transforming sometimes drab royal events to memorable occasions for those who witness them.

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“It is their style of operating that has certainly changed [the monarchy],” Wharfe adds.

Prince Harry. Chris Jackson/Getty

Like many of those who knew her, Wharfe — who has co-written Diana — Remembering the Princess along with journalist Ros Coward — is reflecting on his memories of the late princess as the 25th anniversary of her death is marked this week.

Wharfe had a front-row seat as she raised awareness on a number of causes, including AIDS, homelessness and leprosy — work that took her to those most vulnerable in society. He also saw first-hand how the initial cautiousness and wariness of the royal family when it came to Diana’s modern approach to her role.

Princess Diana. Tim Graham Photo Library via Getty

“Most people meet royals from the other side of the metal barrier. There was no chance for personal dialogue. And yet there was for Diana,” Wharfe says. “She’d single out somebody, engage in conversation, and ask about their health, relationship, their dress or whatever, that would ricochet around the crowd, and everyone would be talking about it.

“And they’d say, ‘We never get this with the Queen or Prince Charles.’ “

Wharfe also saw the pain Diana experienced amid her husband Prince Charles’ affair with his now-wife, Camilla, Duchess of Cornwall.

“I was around in the ’80s and I witnessed on a daily basis with Diana how Camilla was top of the agenda for discussion. It was a thorn in her side. I often wonder how she managed to do her work, away from that discussion, as it became an obsession,” he says.

During Charles and Diana’s joint tour of India in February 1992, it became clear that Charles and Diana were estranged. And Wharfe witnessed the historic moment when Diana sat alone at the Taj Mahal.

When one of the journalists asked Diana what it felt like to be at the historic mausoleum, Diana quietly asked Wharfe, “What do I say?”

“I wasn’t the press adviser, but I said, ‘Say it was a healing experience.’ So she said that and one of the photographers then shouted out, ‘What do you mean by that?’ She got slightly angry and said, ‘You work it out for yourself.’ And we moved on,” Wharfe tells PEOPLE. “She was a consummate performer.”

12 Ways Princess Diana Broke with Tradition and Paved a New Path for the Royal Family

Five years later, tragedy struck in the early hours of August 31 when Diana was killed in a car crash in Paris. Wharfe, a former policeman, has studied the evidence and carried out his own analysis of the crash and agrees with the findings of the official inquest into Diana’s death in 2008 that Diana and her boyfriend Dodi Fayed died because of the “unlawful, negligent driving of the Mercedes and the following vehicles” occupied by the paparazzi. The jury added that the speed or manner of the driving of chauffeur Henri Paul “caused or contributed to” the crash.

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Princess Diana Archive/Hulton Archive/Getty Images

But many people — so desperate for answers as to why someone so famous and beloved could die in such a way, at such a young age — have sought out other explanations.

“That’s why the conspiracy theories abounded,” he says. “Even today, people still tell me they don’t believe it was something as simple as a car accident. It was a series of calamitous blunders. It’s no wonder that people just couldn’t believe it was as simple as that.”