Rumours of a feud between Princes William and Harry round have been swirling ever since the younger brother said 'I Do' and married Meghan Markle.
Reports following Harry's departure from the Royal Family in 2020 claimed the brothers' relationship had become strained after the Duke of Cambridge advised Harry to take things slowly with the American actress.
Biographer Tom Bower's new tell-all book, Revenge: Meghan, Harry and the War between the Windsors, details how Harry failed to notify the rest of the royals when he changed his mobile number.
He claims this confirmed William's fear that Meghan would become a "divisive agent".
In the book, which was released today, Bower writes: "To please her, Harry had split from his old friends. He had even changed his telephone number without telling his family."
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Relations between the brothers were made worse when Harry and Meghan sat down for their bombshell interview with Oprah Winfrey, in which the Duke accused his brother of being "trapped".
A friend of William's said he is still "mourning" the lost closeness.
They told the Daily Mail : "[William] alternates between grieving for what he has lost and feeling really, really angry about what his brother has done.
"He truly loves Harry and feels he has lost the only person, aside from his wife, who understood this strange life of theirs.
"But he believes there are things you just don’t do. And Harry has 100 per cent crossed that line."
Royal expert Duncan Larcombe has now said the pair miss each other, and both feel "a lot of regret" over their changed relationship.
He told OK! : "It’s very clear to those that know William that the rift with his brother is not something that he can just forget about.
"It's very much, as you can imagine, a constant strain. It is for Harry as well, they’re both as stubborn as mules.
"That’s not great when two best friends and brothers fall out. If anybody knows what it’s like to fall out with a best friend or a brother who was close to you when you were growing up, it’s not nice. You miss them."
He went on to add: "There is a lot of regret there and I think it’s on both sides."
