Watch: Harry to publish 'wholly truthful' book on his life in 2022
Prince Harry's plan to write his memoirs could deepen an ongoing rift with the palace, amid speculation that his tell-all book could one day become a movie.
Harry, 36, announced on Monday that he had signed a deal with Penguin Random House to release his memoirs, saying they would be his "first hand" account, and "wholly truthful" – a comment widely seen as a swipe at decades of press reports about him.
Harry's relationship with his family has been extremely strained for several months, culminating in his decision to step back as a senior royal in January 2020.
With the Duke of Sussex already revealing many of his thoughts and feelings in podcasts and interviews since then, reaction has been mixed to his latest announcement.
It has been reported the Royal Family did not know about his plans to release a memoir, and that he did not seek permission, which would not be required now that he is not a working royal.
Speaking to ITV's This Morning, Camilla Tominey warned that royals do not react well to insiders spilling the beans on the royal household.
Alluding to another segment on the morning programme, Tominey, the associate editor and royal expert at The Daily Telegraph said: "'Am I being unreasonable?' might be something Charles and the Queen ask.
"They [Harry and Meghan] went to California to seek a quieter life but now to have this unprecedented memoir..."
Pointing out how previous memoirs had been received by royals, she said: "The Queen disowned her own nanny back in the day because she set down the secrets of royal life."
Tominey added: "He is perfectly entitled to write his own book, I'm intrigued to read it.
"When you talk about 'my truth', you are giving your version of the truth - there are two sides to every story. We have seen their unleashing of their side without a right of reply.
"What can the Queen or Charles or the Duke and Duchess of Cambridge do? They are very unlikely to give their side."
Marion Crawford was governess to the Queen and her sister when they were children, but they stopped speaking to her after she wrote The Little Princesses, a gently respectful account of caring for the sisters.
Prince Charles took out a High Court injunction in the 1990s when his former housekeeper wanted to publish a book on the inner workings of his household.
Gyles Brandreth told This Morning the book "wasn't quite unprecedented", adding: "Queen Victoria released her diaries of summers in Scotland, the Duke of Windsor [released a book].
"When Charles and Diana did this in 1990s it caused a lot of heartache." Both spoke at length to biographers Jonathan Dimbleby and Andrew Morton.
Brandreth also speculated that the memoirs could be translated to the big screen, noting the choice of ghostwriter in the well-respected JR Moehringer.
The former MP added: "I imagine Meghan has been involved in this in some way. They have chosen a Pulitzer winning novelist and his books tend to be turned into movies.
"I don't think it will be called 'recollections may vary', but I think we will see a book next year and then a movie the year after. This will run and run."
The Queen's statement following Harry and Meghan's interview with Oprah Winfrey included the comment "recollections may vary" in response to their account of life inside the palace.
Watch: Prince Harry and Meghan Announce New Netflix Animated Series
Evening Standard royal editor Robert Jobson told the MailOnline: "It will become an international bestseller, but at what cost to the monarchy? There will be nowhere to hide."
He added: "Harry is already hugely rich and famous so apart from damaging his family - which a book like this will inevitably do - I am not sure what he is trying to achieve. Whatever he says will lead to conflict."
Royal biographer Duncan Larcombe told ITV: "A book really really gets to the heart of it potentially. Will he use this as a platform to explain why he is so angry, why he has done what he has done with Megxit, why he walked away?
"We were told they walked away from Britain because they wanted privacy - well that hasn't happened."
Of what the book might cover he added: "Who was the racist in the Royal Family, how can you not address that? Who said what, when, how, what context? Will Harry give his own family the right of reply?
"Harry has complained for many years about not having his own say - is he going to afford his family that luxury?"
He also said the memoirs was something the royals need "like a hole in the head" pointing out it will come out soon after the Queen celebrates her Platinum Jubilee.
Angela Levin, who spent time with Prince Harry ahead of writing Conversations with the Prince, noted that he was full of praise for his father Charles in 2017 when he was guest editing Radio 4, but suggested Charles was "at the top of his list to smash".
She told Good Morning Britain: "I feel he risks looking like a traitor to the Royal Family, I can't believe it will be all honey and sweetness.
"Does he want to destroy his family? Does he feel so vengeful that he has to take yet another knock after Oprah?
"I don't quite get it, why he doesn't want to move on, enjoy his life. He is making pots of money, he is in love with his wife, he has two children but why is he so negative about his past? He can't leave it alone."
Presenter Trisha Goddard said: "You can love and adore someone and criticise something about their past, as Prince Charles loved and adored his father but also had criticised his family about their decision to send him to Gordonstoun.
"I would love to hear about (Harry's) time in Afghanistan. He will be talking about losing a mother at an early age. We don't know that it's all going to be negative.
"Everyone's autobiography is their own truth."
She also pointed out how much Diana had worked with Andrew Morton for his book, for which he later admitted she was the main source.
Prince Harry is understood to have already written the first draft of the book alongside his ghost writer, but the memoirs are not yet titled.
The book is scheduled for release in the US, Canada and the UK in late 2022.
Watch: The Queen's Biography