The title of Prince Harry’s much-hyped memoir is a pun. Spare refers to his role as excess royal offspring. But to go spare is to become distraught. True enough, readers will find out how Harry was born the spare and how he went spare afterwards.

You may question whether you should be reading anything more about Harry, let alone a 416-page book. I questioned whether I should add to the coverage. Here is the case for the defence. Of all Harry and Meghan’s output since they stepped down from royal duties in 2020 — the interview with Oprah Winfrey, the Spotify podcasts, the six-hour Netflix documentary — Spare is the most bearable and revelatory. In the hands of ghostwriter JR Moehringer, acclaimed for guiding Andre Agassi’s memoir Open, Harry’s story is told sensitively and at times movingly.

Arguably Spare is the most insightful royal book in a generation. It might have been even if it simply contained the prince’s bizarre account of being knocked to the floor in 2019 by his older brother — a necklace ripped, a dog bowl smashed. This is royal life, not as imagined by scriptwriters or hangers-on but as experienced by two protagonists, “Harold” and “Willy”.

Harry comes across as honest and reflective, but also angry, thin-skinned, disoriented. The source of his distress is…