It would be unwise and terribly unfair to read too much into the princes’ apparent calm. There is no doubt that both were deeply affected by the death of a mother who had poured so much of her emotional energy into their welfare and made herself so central to their young lives. They have spoken of it since, but only recently have they admitted how angry they were that their mother was so viciously and suddenly taken from them. ‘I can safely say that losing my mum at the age of twelve, and therefore shutting down all of my emotions, had a serious effect on not only my personal life, but my work as well,’ Prince Harry said in April 2017.

‘The shock is the biggest thing,’ Prince William confessed at the same time. ‘I still feel it twenty years later. People think shock can’t last that long, but it does. It’s such an unbelievably big moment and it never leaves you. You just learn to deal with it.’

At that time, however, they could see their mother’s weaknesses as well as her strengths, and fifteen-year-old William had become increasingly concerned at the direction in which her life appeared to be heading. They had spent several days that summer with her in the South of France as guests of Mohamed Al-Fayed, who had pulled out all the stops. In his typically flamboyant style, he provided helicopters, yachts and speed boats and even opened a discotheque especially in an effort to impress them. It was all too lavish, too embarrassing, too over-the-top, too ‘foreign’ as they put it, for young men brought up to believe in the virtue of discreet understatement. Diana was lured by the glamour. Her sons, more royal than she realised, were not.

In her determination to ensure that they should enjoy as normal an upbringing as possible, Diana sometimes inadvertently led them in directions which went against their natural inclinations. William, for instance, much preferred the hills of Scotland to the beaches of the Riviera, shooting to waterskiing, the companionship of his school friends to the company of international playboys like Dodi Fayed, and he was starting to find the programme of entertainments his mother insisted on organising for him increasingly irksome. The prospect of spending the next few years in Mohamed’s jet stream did not appeal in the least.

It did not appeal to the royal family either. An off-the-record call was made to the private office of Al-Fayed by Prince Edward, who explained to Mohamed’s sidekick Mark Griffiths that there was concern over the ongoing Harrods sponsorship of the Royal Windsor Horse Show and it couldn’t continue. Harrods was the main sponsor of the show and when Al-Fayed had taken over he had increased the sponsorship and included a carriage driving competition in which Prince Philip competed.