London: Prince Charles is "furious" with a former close aide for penning a new book which is expected to give details of the breakdown of his marriage to Princess Diana and other royal family gossip, according to a media report.

Prince of Wales, Prince Charles and Camilla Parker Bowles. File Pic/AFP

Charles, 65, has blasted the former close aide for "betraying" him by writing the explosive new book, the Daily Mirror reported.

The Queen's ex-Press Secretary Dickie Arbiter is set to spill secrets about Charles' relationship with Diana and the breakdown of two other royal marriages, the report said.

"Charles is furious. This man was a trusted friend," a palace source was quoted as saying.

For 12 years, Buckingham Palace Press Secretary Arbiter was regarded by Prince Charles as a man he could trust with his deepest secrets, the report said.

Nicknamed Sticky Arbiter, he is set to hang out the Royal Family's dirty laundry and be the first Buckingham Palace press officer ever to spill the beans on what he witnessed behind closed doors.

It is understood officials have been taking legal advice in a desperate attempt to halt its publication, the report said.

"He is raking over the breakdown of the marriage and the Prince has been asking aides 'Why do we have to go through this all again?'" a palace source said.

"It is just a case of a man who he thought was a friend and who could be trusted cashing in on the misery of that time. It is disloyal.

Arbiter has been told that he does not have official permission to write this book and a legal team has reviewed all his old contracts in a bid to try and find a way to stop it," the source said.

The ex-aide, who has previously blasted others for selling royal secrets, stands to rake in around 250,000 pounds from publishing advances and serialisation fees.

He still receives lucrative pension payments from the Royal Family.

It is understood Arbiter's shock disclosures will detail how Princess Diana felt "humiliated" by her husband's affair with Camilla Parker Bowles and her "dark days" as an unhappy wife.

The book is said to reveal how the relationship went "sour" after Diana had been "madly in love with Prince Charles at the start of their marriage."

Arbiter, who claims to have turned down countless previous offers to write his memoirs, said: "This is not just a memoir of an intense dozen years but is a story of a life, my life and it's been quite an extraordinary one."