Butler Paul Burrell says Princess Diana's sons William and Harry haven't spoken to him in 20 years

In a revealing new interview, Princess Diana's former butler Paul Burrell says her sons, Prince William and Prince Harry, haven't spoken to him since her tragic death.

In the interview on Australia's Channel 7 Sunrise programme today, Burrell spoke of his anguish over the lack of contact with Diana's sons since her death in a car crash almost 20 years ago.

"I haven't spoken to them since their mother died in 1997," he told the programme.

"But I'd love to speak to them.

"And I'd love to tell Kate about the incredible woman who changed all the rules to make her life more comfortable.

"To give her a better life as a royal. It's what Diana did."

Burrell hinted that it wasn't William and Harry's decision not to contact him.

"I don't know why (they haven't contacted me)," he said.

"(But) Think about the system. The whole establishment is up against me because I'm the outsider.

"I belong in Diana's world. I'm the one who got away.

"You've never heard me say anything disrespectful about the royal family or the Queen.

"We have a wonderful monarch. She's 91 on Friday, long may she reign."

Prince Harry, right, Kate, the Duchess of Cambridge, center and Prince William. Photo / AP

Princess Diana continues to be revered well after her death. But when Sunrise co-host Natalie Barr put it to Burrell: "She was viewed as a saint, she mustn't have been?" He agreed.

"She was flawed. She was incredible and unique and inspirational," he said.

"She had bulimia and anorexia. Believe me, for all her life it was a condition of how she was treated by other people."

Burrell said Princess Diana had paved the way for Kate to be herself as a royal.

"She's not put a foot wrong. She is incredible," he said.

Paul Burrell signing copies of the 'The Way We Were' in 2006. Photo / Getty Images

"She has something Diana never had, the love and support of a man who adores her. She can't go wrong."

Burrell said he also saw Diana's legacy in her sons.

"I think they are wonderful," he said.

"They are following in their mother's footsteps. She had them for long enough to instil her hopes and dreams and ideals. They are now the product of Diana."

Burrell also spoke of the "dysfunctional" marriage between Princess Diana and Prince Charles, after a new book revealed details of their rocky relationship.

"There were many arguments behind closed doors (but) I never saw that happen (Princess Charles harm Princess Diana)," he said.

"Their relationship was not a great love affair.

Prince Charles, Prince William and Prince Harry attend a ceremony marking the 100th anniversary of the Battle of Vimy Ridge. Photo / AP

"In the beginning, it was. The boys were born out of love but sadly it went wrong because of another person (Camilla Parker-Bowles) in the marriage.

"As Diana said, there were always three people in the marriage.

"His duty was to give a heir and a spare for the royal family. Now she was there at the right place.

"An 18-year-old girl who never had a boyfriend before, a perfect royal from a very good family.

"She was brought into the royal family as a lamb to the slaughter. She was naive, innocent, fresh. All of the things they wanted her to be.

"I'd say, (their marriage was) dysfunctional. I wouldn't say abusive.

"I never saw any physical harm. But mental torture."