A royal biographer feels "perplexed" by the claims made in Prince Harry's memoir.

Jonathan Dimbleby has been baffled by the 38-year-old prince's 'Spare' memoir, observing that it contains revelations that you might to see from a "B-list celebrity".

He said: "I am perplexed. I am at a loss. He is clearly a very troubled man.

"I’m concerned incidentally that everyone uses the word revelations. Yes, there are obviously revelations about how he lost his virginity, taking drugs, and how many people he feels he might have shot down from his Apache. But those are the kind of revelations, in part, that you would expect, I suppose, from a B-list celebrity."

Jonathan, 78, also thinks King Charles will be "extremely pained" by the claims made in the memoir.

He told BBC Radio 4's 'Today' programme: "I can only imagine he is extremely pained, very frustrated and would be very anxious to bring it to an end."

In his memoir, Harry claims that he killed 25 people while serving in Afghanistan.

The prince - who undertook two tours of the country - explained that he killed 25 Taliban fighters during his time in the British army.

He wrote: "It seemed to me essential not to be afraid of that number [of people killed]. So my number is 25.

"It’s not a number that fills me with satisfaction, but nor does it embarrass me."

Harry even likened the Taliban fighters to "chess pieces removed from the board".

Despite this, the prince actually relished his time in the British military as it allowed him to escape the dramas of royal life.

He said: "I was no longer Prince Harry, I was Second Lieutenant Wales of the Blues and Royals, second oldest regiment of the British army."