He told Express.co.uk: “The York brand is toxic and Sarah Ferguson’s support won’t change anything.”

Mr Fitzwilliams also revealed the Royal Family could create a new role for the shamed duke because he will not be able to return to public life.

He added: “Andrew is in the background, though he is trying to arrange a comeback and it is getting him nowhere. Indeed there is even more adverse publicity but public support is near zero.

“He has to accept that, at 62, he has no future public role.

“The Royal Family have to create one for him, such as managing the royal estates.

Andrew stepped down from public life after the furore over his friendship with paedophile billionaire Jeffrey Epstein, and paid millions to settle a civil sexual assault case against a woman he claimed never to have met.

The duke was cast out of the working monarchy and no longer uses his HRH style after Ms Giuffre, who was trafficked by Epstein, accused him of sexually assaulting her when she was 17.

The Duke denied the claims.

Speaking to Mariella Frostrup on Tuesday, Sarah was asked if she would still marry the prince if she could go back in time.

The 62-year-old replied: “Oh, yes. He’s a very good and kind man. He’s a good man.”

Referring to their wedding day, she added: “And it was an exceptional day, July 23 1986. And it was just extraordinary.

She later told the programme: “And, you know, I will stand very firmly by Andrew… a very good and kind man and that’s what I believe.

“We are divorced. I think it’s very important, Mariella, that people realise that I don’t spend long here in England, because I don’t wish to. I’d much prefer being out.

“I’ve built 156 schools in Africa and Poland. And, you know, and I just want to keep going doing my philanthropy work.”

Sarah officially left the Royal Family when she and Prince Andrew divorced in 1996.

The pair still remain firm friends and even share a residence.