Prince Harry will have to be very careful on what he writes in his memoir if he does not want to face another legal dispute, this time against his very own family.

The royal family is said to be concerned about what the Duke of Sussex will reveal in his upcoming book. There are worries that he will publicly shame his stepmother Camilla and slate his father Prince Charles.

Despite his promise that it would contain "wholly truthful" accounts of his life and experiences, he would still need to be "very very careful" according to The Telegraph's Associate Editor Camilla Tominey. She feels that he has to make sure that it is legally sound after describing it to be a "delicate" memoir.

"On one hand, Harry reserves the right to write up his life story in any way that he sees fit. It is interesting and it's probably the strongest shot across the boughs that we've had throughout the whole of the so-called Megxit saga with this briefing that we were given some weeks ago suggesting that the Queen's lawyers would be poring over every line," she said.

Tominey called the briefing over Prince Harry's memoir "a message to America to say don't think you can just write anything that you like as you said at Oprah Winfrey without being challenged on it, without offering a right of reply."

The alleged warning from Queen Elizabeth II's lawyers could potentially change the contents of the book. She said it could alter the title to become "more tepid than we anticipated."

On the other hand, the Duke of Sussex's publisher, Penguin Random House, wants an explosive tell-all. It becomes a challenge then and "could make for uncomfortable reading for the Royal Family." Tominey hopes that Queen Elizabeth II's Platinum Jubilee celebration would be as successful as the one in 2012 so it could overshadow any negative publicity over the memoir.

However, there is still concern that Prince Harry could still taint the family's reputation if he ever "decides to drop a load of bombshells in his autobiography in autumn and they're legally safe, so he's able to publish them without too much of a pushback." No matter the outcome of the book though, she advised the duke about "not causing too much upset" to Queen Elizabeth II given her frail health.

Meghan Markle, Prince Harry, Queen Elizabeth II
"Harry, Meghan and Archie will always be much loved family members," Queen Elizabeth stressed in her statement Photo: POOL / John Stillwell