The Duke of Sussex has denied boasting about killing 25 Taliban while serving as a soldier, as he cautioned against “very dangerous” spin about his memoir.

Protests were sparked by Spare, which on Tuesday became the UK’s fastest selling non-fiction book, due to Harry writing he had engaged in “the taking of human lives” while serving as a helicopter pilot in Afghanistan.

“So, my number is 25. It’s not a number that fills me with satisfaction, but nor does it embarrass me,” he wrote.

The 38-year-old told Stephen Colbert it had been “hurtful and challenging” watching the reactions following the book’s publication.

“Without a doubt, the most dangerous lie that they have told, is that I somehow boasted about the number of people that I killed in Afghanistan,” Harry said on The Late Show.

He noted the context in which the reference appeared in the book, before saying: “I should say, if I heard any one boasting about that kind of thing, I would be angry. But it’s a lie.

“And hopefully now that the book is out, people will be able to see the context, and it is – it’s really troubling and very disturbing that they can get away with it.

“Because they had the context. It wasn’t like ‘here’s just one line’ – they had the whole section, they ripped it away and just said ‘here it is, he’s boasting on this’.

“When as you say, you’ve read it and hopefully everyone else will be able to have the chance to read it , and that’s dangerous.

“My words are not dangerous, but the spin of my words are very dangerous.”

Admiral Lord West, former head of the Royal Navy, had previously called the duke “very stupid” for giving details of his Taliban kills.

The retired admiral told the Sunday Mirror that the Invictus Games – which are due to be held in Dusseldorf, Germany, in 2023 – will have “serious security issues” because of their direct connection to Harry.

The international multi-sport event for wounded, injured and sick servicemen and women, of which the duke is the patron, will be a prime target for those wanting revenge, Lord West said.

“The Taliban will be reading (Harry’s claims about killing fighters and) thinking there’s this prince calling us all chess pieces and is quite happy about killing us.

“And there will be a lot of people, I am sure, in Islamic State and other terrorist organisations, who will think this is something which should be avenged.”

Harry said he was driven to discuss his kills by the goal of reducing veteran suicides.

“I made a choice to share it because having spent nearly two decades working with veterans all around the world, I think the most important thing is to be honest and to give space to others to be able to share their experiences without any shame,” he told Colbert.

“And my whole goal, my attempt with sharing that detail, is to reduce the number of suicides.

The Colbert interview caps off Harry’s press run for his headline-grabbing autobiography, was boosted into the record books with 400,000 hardback, e-book and audio format copies being snapped up.

The book includes claims that the Prince of Wales physically attacked him and teased him about his panic attacks, and that the King put his own interests above Harry’s and was jealous of the Duchess of Sussex and the Princess of Wales.

Harry said in an interview that the Duchess of Cornwall was a “villain” and “dangerous”, accusing her of rehabilitating her image at the expense of his.