A renowned royal historian reports Prince William once broke out in anger, calling Meghan Markle a "bloody woman" who was "merciless" towards his staff, as friends of Prince Harry admit the American can be a "500 percent nightmare".
Prominent royal biographer Robert Lacey makes the claims in a new report published in the Daily Mail. It comes as his 2020 book Battle of Brothers - which dissected how William and Harry split onto their own paths - is republished with new chapters.
In the Mail article, Lacey writes of how the pair continue to feud and that they never met following Prince Philip's funeral in April, despite what was reported at the time.
However, while he says "the conflict between Diana's two bitterly divided sons does not seem likely to end any time soon", friends and family of their pair are trying to "ease the path to a truce". The brothers may have the chance to reunite at an event next week unveiling a statue of their mother at Kensington Palace.
Both sets of friends, Lacey says, can see the other side's view.
"William's defensiveness of the monarchy as he sees it, and Harry's defensiveness of his wife. Love versus duty. This is what makes it so painful," Lacey writes.
He says supporters of the Duke and Duchess of Sussex recognise the "bizarre combination of self-promotion and self-pity that characterises Meghan and can see why it has infuriated William".
"'Meghan can be a 500 percent nightmare,' some close friends of Harry are among the first to admit. 'The never-ending PR. She's just so... American!'"
On the other side, friends of William and Kate admit the pair were jealous of being overshadowed by Harry and Meghan and that they used "sharp-elbowed tactics" to keep the newlyweds in their place.
Lacey says it was pointed out to William that "everyone has a difficult sister-in-law".
"William's response was to nod his head in sage acceptance. Then suddenly he broke out angrily. 'But look at the way that bloody woman treated my staff - merciless!'"
It's said that Buckingham Palace is actively working to bring an end to the "emergency". "Homesick Harry" is also reported by Lacey to have been ringing his UK friends "mournfully" recently.
"I'm told that Harry has been telling friends he would like to reconcile, and is willing to admit some of the missteps he has made."
He arrived in London this week to start his quarantine period ahead of the unveiling of Princess Diana's statue next week. Meghan isn't accompanying him, having just given birth to their second child earlier this month.