The Duchess of Sussex will not want to return to the UK in the future and face curtseying to the Princess of Wales, a royal biographer has suggested.

Andrew Morton, who collaborated with Diana, Princess of Wales on his 1992 book Diana: Her True Story, ruled out a move back from the US for Meghan and the Duke of Sussex.

Morton, asked whether he thought the Sussexes would ever come back to Britain, told Sky News’ Sunday Morning With Trevor Phillips: “What, and have Meghan Markle curtseying to Kate Middleton?

“I don’t think so. I don’t see that as a runner. They’ve got their own lives in California.”

Royal Highnesses bow and curtsey only to majesties, so Meghan would only have to do so to Kate once the princess becomes Queen.

Harry is set for a brief solo trip to the UK without Meghan this week to attend the WellChild awards in London on 7 September, before he heads to the Invictus Games in Germany, where the duchess will join him later.

He is not said to be meeting his father the King, who is reported to have no time in his diary, or his brother the Prince of Wales, amid their continued troubled relationship, which Harry laid bare in his Netflix documentary and Spare memoir.

Harry’s visit falls on the eve of the first anniversary of Queen Elizabeth II’s death and the King’s accession on 8 September.

Harry explored Meghan and Kate’s fractious relationship in his autobiography, recounting how the princess, pregnant at the time with Prince Louis, said she was owed an apology from Meghan after she said Kate was suffering from “baby brain” due to her “hormones”.

The duke shed further light on the row between Kate and Meghan over Princess Charlotte’s bridesmaid dress, saying the incident left Meghan “sobbing on the floor”.

Morton described how Diana had wanted her youngest son Harry to be a “wingman” to William.

She also hoped her husband Charles would move to Italy with his then-mistress Camilla, now the Queen, to spend his time farming and sketching, leaving his eldest son to become King.

Morton said: “Her ambition was to see Prince Charles, her estranged husband, go off to Italy with his lady, being Camilla, and take up farming, sketching, watercolours and the rest of it, and leave her to guide Prince William into his future destiny as King – this is to say, to jump a generation.

“Well, that never happened.”

He added: “She also saw Harry very much as a back up, as a wingman to William in the difficult, lonely job that he will face. Well, that hasn’t happened either.”

Mr Morton was speaking just days after the 26th anniversary of Diana’s death and as unheard audio tapes of the late princess are due to air in an upcoming documentary.

He described how hearing her voice again in the recordings, which were originally given to him with the princess’s permission 30 years ago for his book, was “eerie”.

Extracts of clips were shared through ABC News on Friday to trail the release of documentary Diana: The Rest Of Her Story, and featured Diana talking about how the King expressed disappointment Harry was not a girl at his christening.

Morton said: “It can be quite unnerving, especially when you listen to the parts where she talks about her ambition for the future is to just walk along a street in Paris, we all know what happened.

News comes as Prince Harry and Meghan Markle were spotted enjoying themselves at Beyonce’s Renaissance world tour in LA, days before they head to the Invictus Games.

Read More