Queen Camilla has shared an amusing insight into life at Clarence House with her husband King Charles, revealing the “off-putting” habit that irks her every evening.

Speaking in a new BBC documentary, the 79-year-old royal confessed that the royal couple spends every evening reading together, but his choice of material has been known to ruin her concentration.

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“My husband and I actually read before dinner. We just like sitting quietly and reading. He loves biographies and PG Wodehouse,” referring to the late humorist’s Jeeves & Wooster novels.

“I occasionally, when I’m deep in a book, hear him roaring with laughter about something. It’s very off-putting. I can’t get back into my book, or I’ll suddenly start weeping, but it’s a lovely, quiet time.”

A voracious reader, Camilla also opens up about how she read Lady Chatterley’s Lover “by torchlight” as a teenager.

She was first introduced to the joys of reading by her father Major Bruce Shand, who became passionate about books during his time as a prisoner of war.

“I left school quite young because in my day women didn’t go to universities. So I think reading has been most of my education,” Queen Camilla explains in the documentary.

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“We must have been very, very young when my father started reading to us. I think that’s where my love of reading came from. We were transported into all sorts of other worlds.”

King Charles’ unusual habits at home

This isn’t the only gentle disagreement that the monarch and his wife experience at home. King Charles is known to be very particular about his routine, from his home temperature to his meal schedule and his travel plans.

He is engaged in a continuous “battle” with Queen Camilla about opening the windows; the monarch prefers to let in the fresh air, while his spouse wants to stay cosy and warm.

In the book Charles III: New King. New Court. The Inside Story, author and journalist Robert Hardman writes: “There’s a constant battle about it. He will have opened it. She will creep in behind and shut it. So there’s a lot of: ‘Oh, darling, you shut the window.’ ‘Yes, I have, because we’re all freezing.’ So a lot of banter goes on.”

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Other reports from ex-palace staff include his bathroom rituals, including the monarch allegedly liking one inch of toothpaste to be squeezed onto his toothbrush each morning.

The last Queen Elizabeth II’s son also reportedly likes his baths tepid, insisting that they are filled only halfway. Princess Diana’s former butler Paul Burrell made the admission in the documentary, Serving the Royals: Inside the Firm.

 “The water temperature has to be just tepid,” he said, adding that the tub can only be “half-full” with its plug “in a certain position.”

When it comes to exercise, King Charles doesn’t do things the conventional way either. His son Prince Harry previously shed some insight into his bizarre exercise regime in his autobiography, Spare, revealing that he would often stumble into his father hanging upside down like a bat.

“You might blunder in as he was doing his headstands. He performed them daily, in just a pair of boxers, propped against a door or hanging from a bar like a skilled acrobat.” Harry wrote.

“Prescribed by his physio, these exercises were the only effective remedy for the constant pain in Pa’s neck and back.”

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And last – but certainly not least – King Charles has a very specific routine when it comes to travelling. According to author Tom Bower, the royal never leaves home without his favourite home comforts.

Writing in his book, Rebel King, Tom revealed the long list of items the monarch brought with him during a visit to the Northeast of England.

He recalls: “He [The King] sent his staff ahead a day early with a truck carrying furniture to replace the perfectly appropriate fittings in the guest rooms.

“And not just the odd chest of drawers: the truck contained nothing less than Charles and Camilla’s complete bedrooms, including the prince’s orthopaedic bed, along with his own linen.”