Philip prefers to think of the pitch of the ship and the dazzling Mediterranean light. The sense of liberation as they ease away from the quay. The stomach-clenching excitement when the order for battle stations crackles out of the speakers.

It is harder here, he thinks. The country is exhausted, its cities bombed, its people grey-faced and worn down by rationing and blackouts. In London, Philip walks past ruined buildings without noticing them anymore. Once, he was with a party heading for the Café Royal only to discover that it had been bombed barely minutes before. Dust still hung in the air. There were bodies lying on the pavement, men in evening dress, women in furs and diamonds that glittered in the moonlight. The looters were already there, stripping away jewels from the dead and dying, pulling up satin dresses to rip off nylon stockings.

Philip remembers stepping past and going on to The 400 instead.

That’s how it is during a war. Nobody knows when the next bomb will drop, when the torpedo will hit, when that Messerschmitt will slide out from behind a cloud and shoot you down. There’s a febrile edge to socialising. The knowledge that each night might be the last time you dance, or laugh over cocktails, or kiss a girl, makes it hard to be sensible and go home early to bed. So they stay up, determinedly dancing and drinking and laughing, squeezing every last drop of enjoyment out of an evening.

It is a world away from Windsor Castle. Here, in the Waterloo Chamber, there is little sign of the chaos and destruction elsewhere. The famous Lawrence portraits have been taken down and in their place – Philip squints to make sure he hasn’t imagined this – are bizarre cartoon characters. But otherwise little seems to have changed since the previous century. The King even leant across the Queen to tell Philip that the stage and curtains are the very same ones used by Queen Victoria’s children for their theatricals.

Philip’s head is aching, a ferocious grinding that jabs every time anyone shifts in a chair, sending it scraping across the floor. He feels fuzzy and stale. Perhaps he really is coming down with the flu that was his excuse for not arriving until last night?

‘Go and help with the pantomime,’ Mountbatten urged.

‘I’m not prancing around on stage making a fool of myself in front of the King!’

‘Make yourself useful backstage, then. There must be something you could do. It’d go down very well. The King and Queen like that kind of thing.’

The more Mountbatten pushes, the more Philip digs in his heels. He’s like a dog being dragged to a bath.

‘Philip, you’re halfway there.’ Uncle Dickie can’t understand why Philip is so reluctant to press his case. ‘The King said Lilibet was very taken with you when you saw them in ’41. She’s been writing to you, hasn’t she?’

‘Occasionally.’ Philip knows he’s being contrary but he can’t help himself. Elizabeth’s letters have been more than occasional. Written seriously in a childish hand, he has found them obscurely touching, though he will never admit as much to his ambitious uncle. He is deliberately keeping things light. He is grateful that she hasn’t embarrassed him by asking for his photograph, and he has been careful never to suggest that he would welcome one from her. That would be taking things a step too far. ‘She’s just a young girl, Uncle Dickie. She hasn’t got much to say.’