Anne has no complaints about the way she and Charles were treated as children, even though their parents were not around as much as they would have liked. She thrived in the freedom they had. While to modern eyes this distance looks odd, at the time it was nothing unusual – the fictional world of Enid Blyton’s Famous Five or Arthur Ransome’s Swallows and Amazons shows how often parents were relatively distant figures in children’s lives. Most wealthy parents left their children with nannies and governesses, and they seldom travelled with their children until the advent of cheap flights. ‘They were supportive and never really quibbled about what you wanted to do,’ Anne said. ‘There were occasional comments about was that really a good idea?’

‘We may not have been too demanding, in the sense we understood what the limitations were,’ she recalled recently. ‘But I don’t think that any of us for a second thought that she [the Queen] didn’t care for us in the same way as any other mother did. In the early fifties, when I was growing up, there were still lots of people working and living in the countryside. Information was passed from parents to children, knowledge was absorbed rather than taught. My “knowledge” of ponies, horses and riding was largely acquired that way, by absorption.’

Interestingly, it was her father who really encouraged her riding. When he saw just how good she was – and how much better than her brother – he contacted Sir John Miller, the then head of the Royal Mews at Buckingham Palace and told him to ‘get on with it’. Charles was still at the end of a leading rein when Anne was off jumping and galloping before she had properly learned how to trot. Philip had no reservations about letting his daughter expose herself to the dangers inherent in equestrian sport. ‘It was almost as if he treated her as a son,’ one observer recalled.

He also found the time to introduce his daughter to sailing on the waters of Loch Muick near Balmoral, with considerably more success than he’d had with Charles, and Anne soon became a proficient yachtswoman, as she still is today.

He would also take the children camping on the windblown Highland hills. They would cook over a fire and spend the night in sleeping bags in a bothy built in Victoria’s day as a picnic hut. Again, it was Anne rather than her altogether more delicate brother who derived the greater pleasure from these Spartan escapades. But that, given their physical differences, was inevitable. Charles was a poor athlete; Anne became a first-class tennis and lacrosse player and, most notably, an Olympic three-day event rider.