Prince Harry and Meghan Markle may explain their decision to estrange themselves from the duchess’s father in a future memoir, according to a royal expert.

The 79-year-old, who is approaching his 80th birthday, is no longer on talking terms with his daughter.

He has also not met her husband in a move that he admits makes “no sense” to him.

Speaking on GB News, Richard Fitzwilliams offered an idea as to how we may find out what has gone on behind closed doors.

“Before the engagement, it has never been explained why Harry has never met Thomas Markle”, he said.

“That is something that perhaps will be explained in a future memoir, but this is all very sad business.

“It’s not going to be resolved. The fact that Thomas is appealing to King Charles and so forth is not going to mean anything happens, I’m afraid.

“As far as the wider royal drift is concerned, the Royal Family have other priorities at the moment, putting it mildly.”

Asked by Martin whether there would be “any chance” of a reconciliation for Thomas’s 80th birthday, Fitzwilliams admitted he sees little prospect.

Thomas Markle told the Mail on Sunday that his life has been overshadowed by “what has happened in the last six years”.

He admitted he struggles to understand why he has never met his son-in-law.

"When I reflect back on my life, as you do when you are approaching 80, that’s one of the questions I cannot find an answer for”, he said.

"Why didn’t Harry ever come to meet me?

"He has the resources to fly around the world – and does – but why didn’t he come to see me, particularly when people in the royal household like Jason Knauf [Harry and Meghan’s former communications secretary] were urging him to do so? That has never made sense to me.

"What man gets married without meeting his wife’s father?"

Thomas Markle said he would also like to speak to the King as he believes they have parallels between how they have both been treated by the Sussexes.

He said: "I would love to speak to him because I am sure he has as many unanswered questions as I do. Neither of us deserves the treatment we’ve received.

"He is going through cancer treatment and I’m not in the best of health.

"I’m not afraid of dying. It is what it is.

"I have so many questions I’d like to ask Meghan and Harry.

"The main one being, why have they treated not only me but the Royal Family and the King so badly."