November 2, 2022 | 1:51pm

Charles and Diana’s unhappy marriage was so “highly combustible” that royal protection officers were worried someone would get hurt.

One of Charles’ valets remembers seeing Diana “hurling epithets and mocking her husband’s obsession with the dreary-looking Camilla,” writes Christopher Andersen in the upcoming biography, “The King: The Life of Charles III,” out November 8.

The valet watched on as Diana “literally pursued” her husband “down hallways, up staircases and from room to room” at Charles’ Highgrove House country retreat, Andersen writes.

“Why won’t you sleep with me?” Diana is said to have asked her husband, who “had for all intents and purposes unilaterally called a halt to their sexual relationship,” since Prince Harry’s birth in 1984.

Charles’ sarcastic alleged response: “I don’t know, dear. I think I might be gay.”

The new book “The King: The Life of Charles III” gets into just how bad Charles and Diana’s relationship got.
Charles (with Prince Harry) and Diana (with Prince William) often argued at his Highgrove country estate, according to the book.
Tim Graham Photo Library via Get

During one heated argument, Charles childishly demanded that he be given the respect “that he felt his position warranted,” according to the book.

“‘Do you know who I am?’ he demanded of his wife.

“Diana answered that he was a ‘f–king animal,’” writes Andersen. “You will never be King!” she shouted. “William will succeed your mother. I will see to that.”

The tension in the royal household only increased as time passed.

Even before marrying Charles, the book says, Diana soon realized that her fiancé Charles was in love with Camilla Parker- Bowles.
Getty Images

“The clashes between Diana and Charles were now so raw that ‘violence seemed inevitable,’” one bodyguard notes in the book.

Officers were concerned by the “sheer firepower” contained within Highgrove’s walls, which included shotguns, rifles and pistols, according to the book.

“The detectives in charge of protecting members of the royal family were deeply concerned that ‘in the heat of anger,’ any one of these could be used to commit suicide, homicide or both,” writes Andersen.

Andersen writes that Diana would pursue Charles throughout the house, asking why he wouldn’t sleep with her.

Tim Graham Photo Library via Get

Staffers claim in the book that they were worried things might get violent between the unhappy couple.

Getty Images

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The couple, who married in 1981, were miserable before their fairytale nuptials. Charles reportedly felt pressure from his father, Prince Philip, to marry and was irked that Diana giggled during the proposal, later calling her reaction “juvenile and unnerving.”

Diana, who was 12 years younger, soon realized that her fiancé was in love with his mistress, Camilla Parker- Bowles.

“The King” will be on shelves on Nov. 8.

“Consumed by anger and frustration, both bride and groom separately cried themselves to sleep the night before the wedding,” writes Andersen.

The couple finally agreed to separate in 1992 and divorced in 1996. Just a year later, Diana tragically died in a car accident at age 36.