Nor were there on another occasion when his taunting so annoyed a young footman that he took a swipe at Andrew that deposited him on the floor and left him with a black eye. Fearing for his job, the footman confessed what had happened and offered his resignation. When the Queen came to hear of it, she refused to accept it. She said her son had obviously deserved it and the footman was on no account to be punished for Andrew’s bad behaviour.

By that time, of course, Andrew had a younger brother to keep him company. Prince Edward was born on the evening of Tuesday 10 March 1964 and there at the bedside, holding the Queen’s hand, was the Duke of Edinburgh. It was the first time he had been present at the birth of one of his children and he was there at the express invitation of his wife.

The Queen was thirty-seven. She had not found giving birth easy, but sixteen years had passed since Charles was born and fashions had changed in the interim, even in matters as primary as obstetrics. Now the accent was more on the relationship between mother and baby and how that could be enhanced, both physically and emotionally, by the mother being aware of what was happening – and how important it was to involve the father in the process.

As a keen reader of women’s magazines which had been devoting an increasing number of their pages to articles expounding these theories, she had become fascinated by this new approach. It struck a timely chord. The Queen’s life had always been subject to the advice of others. Even in matters as intimate as how they were delivered of their own children, the royal family had been subjected to checks and scrutiny. Prince Philip had been barred from the birth of Charles, Anne and Andrew. The idea of having him there with her would have been almost incomprehensible to most people, if not distasteful in an age so decorous that it forbade the publication of any photographs of the Queen in her pregnancy and never officially acknowledged that she had delivered her first-born by Caesarean section. But this time, she decreed, Philip would attend the birth – the first time in modern history that any royal father had been allowed in to see his progeny born.

More sensitive than his abrasive public image suggests, Philip took a concerned interest in the proceedings, and when the spirits of others started to wane, his cheerful banter revived them. As with Andrew, the baby was born in the bathroom of the Belgian Suite, which had once again been converted into a delivery room. During the Queen’s confinement, black drapes were hung over the floor-to-ceiling French windows which look out over the terrace to the palace gardens and the lake.