For the Queen and Prince Philip, who were celebrating their fortieth wedding anniversary, and the Queen Mother, who was about to celebrate her eighty-seventh birthday, it was a sorry episode. The Queen Mother was incensed and told Andrew, Edward and Anne (who each captained a team, along with the Duchess of York) that she had spent years building the reputation of the monarchy with the King only to have them try to destroy it in one evening. Her underlying fear was that everything her daughter had strived to build since the beginning of her reign by hard work and duty could so easily be erased by the behaviour of her own grandchildren and the vigilant press attention they attracted.

As the Queen’s confidant the Right Reverend Michael Mann, former Dean of Windsor, explained: ‘For the best reasons in the world, younger members of the royal family wanted to make the monarchy more approachable. I think the supreme example of that was when they all participated in It’s a Knockout. It was making it a soap opera.’

In 1988, the Queen and Prince Philip were overjoyed when Sarah and Andrew had their first child – and their fifth grandchild. She was named Princess Beatrice after Queen Victoria’s youngest daughter. The Queen was at Balmoral as usual, but four days after the birth Sarah made the effort to travel to Scotland so the Queen and Philip could see the baby before Andrew returned to his ship in the Philippines. Having grandchildren of her own made the Queen more aware of the kind of world they would one day inherit.

Philip and Andrew have never been close and Philip often couldn’t resist taking a verbal swipe at his middle son whenever the opportunity arose. But in those early days he got along well with Sarah, though that was soon to change when their marriage fell into difficulties, something that came about relatively quickly after they had a second daughter, Princess Eugenie, who was born on 23 March 1990. By March 1992, they announced their separation and suddenly the Duke of Edinburgh’s attitude changed. Unsentimental and dispassionate, he only ever spoke badly about one of his children’s partners and that was Sarah.

In the end, he just couldn’t be in the same room as her, and if she came in one door he would leave by another. When the couple finally divorced in 1996, he refused to allow her in any of the royal residences if he was there, and that has applied to this day. He simply felt she had let down the Queen and the institution of the monarchy by her indulgent behaviour and was no longer to be tolerated. However, Andrew has not only chosen not to remarry, but remains on close terms with his ex-wife, despite the disapproval of the Queen and Philip.