There are two narratives in Robert Hardman’s Charles III. The first is an account of the King’s first year on the throne. This is superbly researched and fascinating. We learn, for instance, that when Queen Elizabeth II died, the state trumpeters were on a plane to Canada and the bearer party was in Iraq. (Their first order on their return was to get a haircut. Their second to carry a comb.)

The second is about magic, but since Hardman doesn’t admit this explicitly, the book has the flavour of an intellectual trying to cast a spell. I don’t understand why royalists can’t just say that a monarch occupies a space to prevent something worse occupying it. Monarchism is practical, is the royalist line, considering what people are. It is republicans who are dreamers. Perhaps this isn’t interesting enough. Or perhaps it is the flip side of our British good sense. This is where we go wild, and camp.

The King excluded most of the ancient nobility from the coronation and replaced them with Ant and Dec

Hardman, a newspaperman in the old style, is trusted by the royal family and is rewarded by interviews with the Princess Royal and Annabel Elliot, the Queen’s sister. The latter paints a portrait of Camilla as an unassuming person, who ‘might have that extra glass or that extra biscuit or whatever’. The detail is glorious. Camilla’s family call her Lorraine (for la reine), but any theory that the King and his wife are cousins through Edward VII gets short shrift from Hardman.

The best interview is with the Princess Royal. When the imperial state crown was removed from her mother’s coffin, she admits she felt ‘rather weirdly… a sense of relief – that somehow it’s finished’. Another good interviewee is Richard Chartres, the former Bishop of London, who, on the exhaustion of being royal, imagines that ‘geniality kills in the end’.

King Charles emerges as very odd: how could he not be? He is the first monarch in four generations to be born to it: Elizabeth II, George VI and George V were accidental monarchs, and this may explain their comparative realism. ‘He can cry at a sunset, that one,’ says a courtier of Charles, and I believe it. A bullied child, and an intellectual among George Formby fans, he curls himself into nature. Is it an opportunity to feel small but happy? He dreams about gardening, and plants mazes. He was picking mushrooms when he was informed of his mother’s death.

There is a ruthlessness, too, which the Windsors excel at. Charles excluded most of the ancient nobility from the coronation and replaced them with Ant and Dec because there is only so much room at the top. (And I do not believe that his saying ‘Back again, dear, oh dear,’ to Liz Truss in front of news cameras merits the innocent spin Hardman gives it. He calls it ‘a typically Charles-ish sympathetic remark because Truss had already been at the Palace earlier for a Privy Council meeting’. Really?) There are wonderful anecdotes about peers asking to bring their pages and carriages to the coronation, and to crown themselves with coronets, but it was considered too elitist. This is the negotiation of a modern constitutional monarch, and he did not hesitate – though he overruled the Earl Marshal on coronation robes for peers if they weren’t too threadbare. He likes pretty things.

The best descriptions in the book are of the preparations for the coronation. The Earl of Shrewsbury was not allowed to carry a white wand in the procession, so it stayed in his gun room. The holy oil was harvested in Jerusalem, scented with sesame, rose, jasmine, cinnamon and orange blossom, and consecrated at the Church of the Holy Sepulchre. The King remarked on his grandfather George VI’s tiny head, and told the Archbishop of Canterbury: ‘You have to jam it [the crown] on.’ St Edward’s crown was nicknamed ‘Patek’; the imperial state crown was ‘Rolex’. The word ‘imperial’ was erased from the order of service; the Koh-i-Noor diamond, ‘taken’ from India, was not used. Rehearsals for the coronation used crowns from a theatrical hire shop with ‘Zadok the Priest’ playing on an iPad and Lambeth Palace’s head gardener standing in for the King.

There is magic everywhere in this book, but Hardman does not comment on what power led ponies to bow their heads as Elizabeth II’s coffin passed them. Like monarchy itself, his account has a mad duality – sacred and pedestrian. My favourite anecdote has the King waiting outside the abbey because the Prince of Wales is late. ‘We can never be on time,’ he said, ‘There’s always something…This is boring.’

That is the last thing it is, but kings are different. Hardman has his face so close to the glass he can only see his own reflection – just like us.