Harry and Meghan warned they must do 'one thing' to mend relations with William and Kate

Royal expert Richard Eden believes that in order to do this, both Harry and Meghan must step forward and apologise.

He said on the Palace Confidential podcast: “I’ve been speaking to people about the chances of a reconciliation between the brothers.

“But everyone really has made the same points that it won’t happen until Harry and Meghan really apologise for everything they have said.

“They need to apologise, at least privately, but also how can there be that reconciliation when William and Catherine just don’t know what will later appear in a TV programme or in a book?

“Genuinely, once you’ve lost that trust you’ve kind of lost it forever.”

Prince Harry and Prince William have been reunited a few times since the release of Spare last year. However, the brothers are believed to have not spoken, including at the King’s Coronation last year.

This summer, both princes attended a family funeral for a Spencer relative, but they are believed to have kept their distance from one another.