Prince Harry's outbursts left the late Queen puzzled as she thought he and Meghan Markle were "quite mad", a new book has claimed.
Royal correspondent Robert Jobson wrote in his new book 'Our King' that the late monarch had witnessed some "volatile exchanges" between Harry and his brother William.
The author added that when the Duke and Duchess of Sussex began publicly criticising both the monarchy and members of the Royal Family, the late monarch became "tired", despite having "great affection" for Harry.
Queen Elizabeth also thought Harry was "so consumed" by his love for Meghan that it was "clouding his judgment", the royal correspondent added in his book.
An extract of the book, which is being serialised by the Daily Mail and Mail on Sunday this weekend, reads: "In truth, by the time his grandmother died, Harry had precious few supporters left in the family. Even the Queen, who had always had great affection for him, eventually tired of his outbursts.
"First, she had wearied of the volatile exchanges between Harry and his brother, which sometimes took place in her presence. Then Harry and Meghan had started publicly criticising both the monarchy and members of the Royal Family."
The book adds that the Queen "felt let down" by Harry's decision to step down from his royal duties, but also considered the Sussexes' departure as "a missed opportunity".
Despite that, however, the Queen hoped Harry would "find peace and happiness" in his new life.
Mr Jobson wrote that Harry regularly phoned his grandmother after moving to California, but she felt "troubled" when he asked her to voice his grievances, at which point she asked her grandson to speak to his father directly.
That, however, did not work out, as Harry himself revealed in the Oprah Winfrey interview that Charles had stopped taking his calls.
The new book also claimed that the Windsor walkabout - which saw William, Kate, Harry and Meghan come together after the Queen's death - last September was just "an illusion".
During the walkabout, the "Fab Four" thanked well-wishers who had travelled to pay their respects.
A royal source claimed Prince William decided to put months of tension and upset with his brother Harry aside by offering an olive branch to show "unity".
Speaking after the walkabout, a royal source said: "The Prince of Wales thought it was an important show of unity at an incredibly difficult time for the family."
While the Sussexes' biographer Omid Scobie tweeted that William had made the decision "in the eleventh hour".
But Mr Jobson revealed in his book that Kate found the walkabout "hard", as he wrote: "Catherine later admitted to a senior royal that, such was the ill feeling between the two couples, the joint walkabout was one of the hardest things she'd ever had to do."
The new claims came as Harry and Meghan were said to be "on the brink" of revealing whether they will attend King Charles' Coronation.
There is less than a month to go before the historic event at Westminster Abbey, and it's still not clear whether the Sussexes will be attending or not.
