Jamie Lowther-Pinkerton has never been to Club H, the infamous club in the basement at Highgrove House, where Princes William and Harry used to invite their friends to party away from the prying eyes of the press. In fact, he’s never even heard of it, he says, which seems bizarre for someone who was private secretary to the princes (and, latterly, Catherine, now the Princess of Wales) for eight years from 2005, when the boys were in their twenties. “Oh that,” he nods when I explain what it actually was. “Oh, I do remember it, but, you know, I was working for them, there had to be a line. They were very sweet, but if I had gone to this club and reverted to scallywag type it would have been very difficult.”

In Harry’s wildly successful and controversial memoir Spare, Lowther-Pinkerton (or JLP as the princes used to call him) is not a scallywag but one of the few royal staffers about whom the Prince is nice. He describes him as “deeply calm, slightly stiff… he didn’t deal in bullshit. He didn’t give it, didn’t take it… his finest trait was his reverence for the truth.”

JLP was the man to whom Harry went when he wanted to see photos from the night his mother, Diana, Princess of Wales, died, and the man whose counsel helped fix the bad press after young Duke dressed up as a Nazi at a fancy-dress birthday party. “That particular occasion was just lack of thought,” says Lowther-Pinkerton now. “Nothing needed to be explained to him, the moment it came out he went, ‘what an idiot’… and afterwards it was his motivation to go back to Berlin and honour the people he had offended. They were both bright lads, in their own way.”