Harry and William’s relationship is now hanging in the balance as King tries to keep the line open

In his memoir, Prince Harry will claim how unfair it was that he was always forced to play “second fiddle” to his older brother and heir to the British throne, Prince William.

The relationship between the Prince of Wales and his estranged brother is hanging by a thread ahead of the release of Harry’s revealing memoir, sources have said.

Insiders fear the brothers’ strained relationship is likely to be further damaged by attacks on Prince William and his wife Kate in the controversial book, which is due out next week.

The memoir is said to be “tough on William” and includes a description of a fight between the brothers and “a broadside” against Kate.

The Duke of Sussex was also reportedly warned that Camilla, Queen Consort’s reputation is a “red line” for his father King Charles.

The relationship between the Prince of Wales and his estranged brother is hanging by a thread ahead of the release of Harry’s all-encompassing memoir. Pictured: The Duke of Sussex and the Duke of Cambridge at the unveiling of a statue they commissioned for their mother Diana, Princess of Wales, in the sunken garden of Kensington Palace on her 60th birthday on July 1, 2021

Pictured: Prince William (second right) Kate, Princess of Wales (right) Prince Harry (left) and Meghan, Duchess of Sussex (second left) leave the house after greeting Queen Elizabeth II at Westminster Hall Have attended state in September

Charles has been hurt by the criticism leveled at him and other senior royals in Harry’s Netflix series (pictured) with wife Meghan

Prince Harry’s comprehensive memoir Spare (left) is due to be published next week and he has reportedly been warned that Camilla (front right in photo right) is a ‘red line’ for his father King Charles (front left).

The king is said to be doing better than his eldest son but is already hurt by the criticism leveled at him and other senior royals in Harry’s Netflix series with wife Meghan.

Sources say that while the king is deeply hurt and confused by Harry’s actions, he is still keen on keeping a line of communication open, however cautious. “Whether Prince William would be as receptive is another question,” a source said.

‘Things are hanging by a thread as they are over the past few months and from the sound of it, Harry’s memoir is unlikely to help.’

The Daily Mail has previously reported that while friends are finding it hard to believe the brothers will never speak to each other again after everything they’ve been through, William feels betrayed and angered by his brother’s constant attacks on the royal family .

There is also a big concern that anything they say privately could be made public by either Harry or Meghan.

While Buckingham Palace has declined to comment or engage in a public row with the Sussexes, there is a level of “concern” about Harry’s memoir.

A source with knowledge of the book, provocatively titled Spare, told the Sunday Times they believed it would do irreparable damage to the brothers’ relationship.

The source said: “In general, I think the book [will be] worse for them than the royal family expected. Everything is disclosed. Charles comes off better than I expected, but it’s particularly hard on William, and even Kate gets a bit of a broadside.

Insiders fear the brothers’ strained relationship could be further damaged by attacks on Prince William and his wife Kate in the controversial book. Pictured: Prince William and Prince Harry walk side by side after watching the floral tributes to the late Queen Elizabeth II outside Windsor Castle September 10

‘There are these minute details and a description of the quarrel between the brothers. I personally can’t see how Harry and William can reconcile after that.’

Harry shows Meghan a text he received from William after her Oprah interview as featured in the Netflix series Harry & Meghan

The book will effectively center around the sibling rivalry between Princes Harry and William, a source told The Sun.

They said it will show that Harry’s “bitterness and feelings of injustice” over his older brother’s birthright to be king means he has always “played second fiddle to older William”.

But their mother Princess Diana warned the siblings that they “must never fight” as they need each other, the source said, adding that it was “very sad” that their argument had come to this.

In the Harry & Meghan Netflix series, Harry, 38, accused his father of lying to him when the family tried to broker a “Megxit” deal for the couple at a crisis summit in Sandringham in January 2020.

He said it’s “terrifying that my brother is yelling and yelling at me and my father is saying things that are just not true, and my grandmother is sitting still and kind of taking it all in.”

He also claimed senior royals are jealous of Meghan’s popularity and are trying to tear her down by spreading negative stories against her in the media.

“Charles is coming out [Harry’s memoir] better than I expected,” said a source

The Sunday Times source said the book – due to be published on January 10 – explores Harry’s grief at the death of his mother, Princess Diana.

They said: “The overall impression is that this is a man who never recovered from the trauma of his mother dying so young and then Meghan comes along and he projects a parallel to Diana for her.”

Spare was written by JR Moehringer, a Pulitzer Prize-winning former journalist who also ghost-wrote Andre Agassi’s best-selling autobiography.

The book’s publisher, Penguin Random House, claims it will be a “groundbreaking publication” that tells its story with “raw, unflinching honesty.”

Harry is also expected to give two high-profile television interviews to promote it.

He has already reportedly taped an ITV interview in California with News At Ten host Tom Bradby, a former royal correspondent who has known both William and Harry for decades.

The second television interview will be conducted with the CBS broadcaster in the USA. It will be helmed by news anchor Anderson Cooper and is scheduled to air on Sunday.

Publication sources also said Harry was expected to do at least one newspaper interview, possibly with the New York Times. Buckingham Palace is expected to remain silent on its allegations. But they are unlikely to end with his memoirs.

After retiring as working royals, Harry and Meghan struck lucrative deals with Netflix, Spotify and Penguin Random House signing them on for more projects. Her publishing deal is said to relate to four books, including a bombshell memoir by Meghan.

The 41-year-old Duchess is known to have kept a personal diary during her stay in the UK.

She has previously published a children’s book, The Bench, with the same publisher, and the couple are said to be working on a book about “wellness.” However, some have warned that there could be a risk of overexposure following her Oprah interview, the Netflix series and Harry’s memoir.

A senior Hollywood executive told The Mail on Sunday: “If I were to advise her, I would warn against getting a book out too quickly because there is a very real danger that people will start to experience ‘Sussex fatigue’.

“There comes a point when people feel like they’ve heard the same stories too many times. You need to change the narrative at some point and focus on the future instead of the past.’