After 70 years on the throne, every aspect of the relationship between the monarch and her prime ministers must surely have become deeply, even sometimes wearyingly, familiar to Elizabeth II. Fourteen very different men and women have held the country’s highest political office since 1952 – 10 Conservatives and four Labour. Ideologically, they cover a wide spectrum of views. Yet they have all been united by one thing: the intense care they have taken never to embarrass the Queen in the slightest way. Until Boris Johnson. The thought of having to make a public apology to the monarch like the one that Johnson made on Friday would likely have sent shivers of shame down the spines of every one of his Downing Street predecessors. From Winston Churchill to Theresa May, it would be hard to think of a more humbling and cringeworthy moment than having to apologise for their staff partying on the eve of the monarch’s husband’s funeral in the midst of a plague. But Johnson is a precedent buster as well as a rule breaker. He is said to have also apologised to the Queen in 2019 when the unlawful prorogation of parliament was overturned by the supreme court. But there has never been a more humiliating prime ministerial grovel than the one he made this week. That is not to say that all previous prime ministers have behaved with equal tact and deference in every aspect of the relationship with the palace. During the short reign of the Queen’s uncle, Edward VIII, in 1936 there was a full-on political battle between the government and the king over whether he would marry Wallis Simpson, an American divorcee. The then prime minister Stanley Baldwin told the king to his face that the government would resign if he did not abdicate. When the king asked for time to consult his friends, Baldwin replied tartly: “Who are they?” Edward gave in. During her own reign, the Queen has sometimes had periods of brittle relations with certain prime ministers. Edward Heath’s and Margaret Thatcher’s hostility to the prospect of Commonwealth sanctions against South Africa caused tensions with a monarch whose devotion to the grouping is second to none. Yet according to Thatcher’s biographer Charles Moore, both she and the Queen remained very sensitive to the other’s role and views, in spite of the lurking disagreement. Tony Blair offended some traditionalist courtiers when he pressed the Queen to respond with more public sensitivity to the displays of distress after the death of Diana, Princess of Wales in 1997. Palace traditionalists attempted to get their own back on Blair by claiming he was getting above himself during the Queen Mother’s lying in state in 2002. But there has never been any suggestion that the Queen herself took this view. Blair’s memoirs, like those of other prime ministers, are respectful and deferential towards her. Long ago, the Victorian constitutional expert Walter Bagehot said the British monarch had three rights when meeting a prime minister: to be consulted, to encourage and to warn. Johnson has added another one to the list: the right to an apology.