The royal family led by King Charles III and his heir, Harry's elder brother William, have maintained a studied silence as painful details from the book and a round of pre-publication TV interviews have piled up.

But palace insiders quoted in the UK press said the Duke of Sussex had crossed a line in attacking Queen Consort Camilla, Charles's second wife following the death of Princess Diana, William and Harry's mother.

"He has been kidnapped by a cult of psychotherapy and (wife) Meghan," one royal source told The Independent newspaper.

"It is impossible for him to return (to Britain) in these circumstances," it said, as other sources accused Harry of betraying both his father and brother.

The book opens with an epigraph drawn from the US author William Faulkner — which Harry writes he found on the website BrainyQuote.com.

"The past is never dead. It's not even past," it says, setting the stage for 416 pages of ghost-written prose dominated by Harry's trauma over Diana's death, score-settling with his family and hatred of the British media.

Some UK bookshops staged Harry Potter-style midnight openings for the biggest royal publication since the late princess of Wales collaborated with Andrew Morton for Diana: Her True Story in 1992.

One-person queue

But there was none of the initial clamour and crowds that greeted the sales of JK Rowling's popular adventures of the boy wizard.

At the head of a small queue outside one shop at London's Victoria train station was Chris Imafidon, chair of an education charity, who said he wanted to hear about Harry's life "from the horse's mouth".

Staunch royalist Caroline Lennon, 59, was the only person in line outside another London bookshop before it opened on Tuesday — outnumbered by a scrum of reporters.

"I love the royal family, all of them, but I like Harry too," the Londoner said.

"I don't like this war thing going on between them and I want to hear what he has to say.

"I also bought the audiobook so I will be able to listen to his voice," she added, as both the print and audio versions topped Amazon UK's sales chart.

The publication has been accompanied by four television interviews in the UK and the United States, where Harry now lives with Meghan.

In one session with the US network CBS, Harry described Camilla as "the villain" who waged a "dangerous" campaign to win over the press herself after Diana's death in a Paris car crash — which he blames on the press.

The contents of the memoir, which will be available in 16 languages as well as the audiobook, have already been widely leaked after copies mistakenly went on sale early in Spain.

Popularity plunge

As well as giving insights into palace life, the book contains an explosive claim from Harry that William physically attacked him as they argued about Meghan.

It also gives an account of how he lost his virginity, an admission of teenage drug use and a claim he killed 25 Taliban fighters while serving in Afghanistan with the British military — which earned him a rebuke from both the Taliban and UK veterans.

The book comes on the back of the six-hour Netflix docuseries Harry & Meghan, in which the couple again aired their grievances with the royal family and the British media.

If the couple hope to elicit sympathy, recent polls appear to show that they are having the opposite effect — at least in the UK.

A YouGov poll on Monday found that 64% now have a negative view of the once-popular prince — his lowest-ever rating — and that Meghan also scores dismally.

They may also be straining public interest in Meghan's homeland, after resettling in California, according to the New York Times.

"Even in the United States, which has a soft spot for royals in exile and a generally higher tolerance than Britain does for redemptive stories about overcoming trauma and family dysfunction, there is a sense that there are only so many revelations the public can stomach," its former London correspondent Sarah Lyall wrote.

Harry maintains he wants a rapprochement with his father and brother, despite a lack of contact with them, but said the onus was on them, refusing to confirm whether he would attend Charles's coronation in May.