The Duke and Duchess of Sussex have launched a scathing attack on a “deranged” author whose new book claims Queen Camilla once told a friend: “Meghan’s brainwashed ‌Harry.”

The royal couple hit out at Tom Bower, the author of Betrayal: Power, Deceit and the Fight for the Future of the Royal Family, criticising his “fixation” on the pair.

Extracts from the book, which is being released later this month, also claim the Prince and Princess of Wales considered Meghan “a threat” as tensions escalated before the Sussexes’ decision to quit Britain for the US.

On Saturday, the Sussexes issued a statement responding to the claims in the book, saying Bower’s “commentary has long crossed the line from criticism into fixation”.

They added: “This is someone who has publicly stated, ‘the monarchy in fact depends on actually obliterating the Sussexes from our state of life’, language that speaks for itself.

“He has made a career out of constructing ever more elaborate theories about people he does not know and has never met. Those interested in facts will look elsewhere; those seeking deranged conspiracy and melodrama know exactly where to find him.”

In extracts released on Friday, the book also appears to suggest Harry was “shocked” by the downfall of Andrew Mountbatten-Windsor after revelations about his association with the American financier Jeffrey Epstein, a convicted sex offender.

“The unpredicted and unimagined humiliation of Andrew shocked Harry,” Bower wrote. “Rightly, Harry fears that the future King William could remove all the Sussexes’ titles and effectively banish him from Britain.”

The book also alleges that Megan told William: “If you don’t mind, get your finger out of my face,” during a teatime reconciliation meeting that had “spun out of control”, held shortly after the Sussexes returned from their honeymoon in 2018.

Bower also writes about the pair’s Netflix deal and appearance at the 2025 Invictus Games, founded by Harry for wounded, injured and sick military personnel and veterans, calling them “the Meghan Games”. He claims that, after the perceived failure of the couple’s deal with the streaming company, “Harry agreed that [Meghan] could star” at the sports tournament.

In an extract, Bower cites two Canadian executives dismissed from the games, who “resented the pushy Sussexes”. They claimed that “Meghan was a distraction from the injured veterans”.

Harry has continued his battle against the media this year. In January, he accused the publisher of the Daily Mail of wanting to drive him “to drugs and drinking” by placing his life under surveillance, as he told the high court that it continued to “come after” him and his wife. Speaking in court on the verge of tears, he said Associated Newspapers Ltd (ANL) had continued to make Meghan’s life “an absolute misery” during his litigation against it.

Before the legal proceeding began, Meghan accused the Daily Mail in December of breaching “clear ethical boundaries” by reporting from the bedside of her estranged father, Thomas Markle, after his claims that he had not received his daughter’s messages. ANL denies all the allegations of wrongdoing.