Princess Charlotte set to be gifted 'one the grandest titles' as King Charles maps out Royal Family's future

King Charles is thought to have personally made the decision, eager to ensure Charlotte still has an important role in the family when her older brother, George, becomes King.

Jobson writes: "Sensitive to the fact that nine-year-old Prince George's future is already mapped out, Charles has been careful to reserve one of the grandest titles for Princess Charlotte – currently called Lottie by her mother and Mignonette (French for cute little thing) by her father.

"Although the King has made his brother Edward the new Duke of Edinburgh, the title is only for life.

"After Edward dies, Charles has made it clear Charlotte (now aged seven) should become Duchess of Edinburgh."

The book makes no mention as to what title Prince Louis, the youngest of Kate and William's three children, may one day be given.

As well as carefully planning what future role Charlotte should have, the King is also thought to have held talks with aides on the future of Meghan and Harry.

Their continued use of the titles "the Duke and Duchess of Sussex" has been "discussed at the highest level" according to Jobson's book.

He says that while the King is thought "not to be in favour" of axing the moniker, despite pressure from Palace officials.

The author wrote: "The idea of stripping Harry of his Duke of Sussex title has been discussed at the highest level.

"The King is said not to be in favour, but other senior Royals are less indulgent.

"Ultimately, despite Charles's enduring love for his son, he will come under increasing pressure if Harry continues to attack the monarchy.

"At that point, the King would have two options: put up with the spreading stain on his reign, or take action to limit its scope.

"In short, Harry and Meghan could yet find themselves demoted to Mr and Mrs Mountbatten-Windsor of Montecito, California."