Princess Diana's former bodyguard says he's certain she would still be alive today if he had been in the car with her on the night she died in a Paris car crash.

Lee Sansum told The Sun security guards drew straws to accompany the royal's bodyguard Trevor Rees-Jones in the car on that fateful night in August 1997.

"It could have been me in that car," Sansum told the publication.

"We drew straws to see who would be accompanying Trevor that weekend. I pulled a match and it was a long one.

"When I learned [Diana and Dodi Al Fayed] were not wearing seatbelts in the crash I understood why they didn't survive. That shouldn't have happened.

"It was standard practice for the family to wear seatbelts. It was an order sent down from the boss, Dodi's dad Mohamed Al Fayed. Dodi, in particular, hated wearing seatbelts and I always insisted on it."

Sansum said Diana had given him the nickname Rambo and claims she once confessed to him she was worried about being assassinated.

"I had seen her in tears ... when she learned of the murder of her friend, the fashion designer Gianni Versace. She confided in me her own fears that she might one day be assassinated.

"She asked if I thought his murder outside his home was a professional killing.

"I thought it was. Then she said something that always stayed with me - 'Do you think they'll do that to me?' She was shaking and it was clear from her tone that she really thought that they might, whoever 'they' might be.

"I spent some time reassuring her that no one was going to try to kill her and she was safe with us, but she definitely thought there was a risk that one day she might be assassinated."

Sansum told The Sun he doesn't believe Diana was murdered.