Queen Elizabeth had 'sharp words' with Prince William after he took his son Prince George, on a helicopter flight, according to a new book.
The book, Our King by Robert Jobson, claims the late Queen was unhappy after her grandson chose to defy her wishes against all flying together, and travelled alongside his wife and their children.
It is said the royal feared such a trip could wipe out multiple heirs if a tragic accident were to happen.
According to unofficial protocol, as the heir to the throne, Prince William should never be on the same flight as King Charles or Prince George, as an accident could threaten the future of the monarchy.
Writing in the book, Mr Jobson said: "Which was why she had sharp words with William after he defied her wishes by taking a helicopter flight to Norfolk with all his immediate family.
"She had warned him against flying with George in case of an accident, telling her grandson he always had to be aware of the succession."
The flight was captured in photographs at the Royal Air Show in Fairford in 2016, with Kate, William and George on board.
And again in 2021, William and Kate, along with their three children George, Charlotte and Louis, were all seen boarding a helicopter in the grounds of Kensington Palace.
Following the Queen's death, Wills is now first in line to the throne, with George second, Charlotte third and Louis fourth.
Wills' brother Harry, the Duke of Sussex, is fifth in line to the throne.
King Charles has been hailed for the way he has conducted himself during his 'stand-off' with the Duke and Duchess of Sussex amid their doubted attendance of his and the Queen Consort's Coronation.
There is less than a month to go before the historic event at Westminster Abbey on Saturday, May 6 and it is still not clear whether the Sussexes will be attending or not.
Charles made it clear that he wanted his youngest son and his wife to be part of proceedings, but their silence has exacerbated doubts on whether they will travel across the Atlantic at all.
The monarch has been praised for "playing a blinder" for putting the ball in the Sussexes court, which could backfire if they do come attend the service.