As King George V grew older, he became increasingly alarmed at his son and heir’s behaviour. The Prince of Wales exchanged one married mistress for another and eventually took up with the most undesirable one of all – Mrs Wallis Simpson, an American divorcee. His wilful reluctance to find himself an appropriate girlfriend who would make a suitable wife inevitably focused attention on the heir presumptive, the young Princess Elizabeth. But, in the regal manner, nobody in any of the royal households broke the code of discretion and referred to the looming crisis. ‘Maybe the general hope was that if nothing was said the whole business would blow over,’ the princess’s governess, Marion Crawford, said.

Given the increasing possibility that the princess would eventually ascend to the throne, Queen Mary believed it was vital that Elizabeth should study genealogy to understand that comedy of bloodlines descended from Queen Victoria, which provided Europe with its royal houses. She insisted that history, too, was important, as was poetry (‘wonderful memory training’) and a knowledge of the geography of the British Empire. But maths?

‘Was arithmetic really more valuable,’ the Queen wanted to know, ‘than history?’ Money is not a subject of practical concern to the royal family, so Elizabeth, the Queen observed with telling foresight, would probably never have to do her own household accounts. Crawfie took note. ‘Queen Mary’s practical suggestions were most welcome and I revised the schoolroom schedule for Princess Elizabeth accordingly.’

Whether the Duchess of York ever knew about this, and if she did, whether she cared, is not recorded. The answer in both cases is probably not. The Yorks, so determinedly bourgeois in all other things, simply did not consider a full and rounded education a matter of any great importance for their children’s welfare. ‘No one ever had employers who interfered so little,’ the governess noted. Fortunately, the princess was able to learn by experience. Before she was ten years old she was present at the celebration of her grandparents’ Silver Jubilee in 1935 and the weddings of her uncles George Duke of Kent and Henry of Gloucester, at which she was a bridesmaid.

Of far greater concern to the Yorks was the Prince of Wales’s affair with Wallis Simpson. It was a liaison scored with the hallmark of catastrophe – for the country, for the crown and most particularly for the Yorks themselves. When George V died on 20 January 1936 (by the hand of his doctor, it transpired, who killed him with a lethal injection of cocaine to ensure that the announcement of his death would make the next morning’s edition of The Times and not the less respectable evening papers), it meant that the princess’s Uncle David was now King Edward VIII. His hold on the crown, however, was less than Wallis Simpson’s hold on him and later that year he would let go of his birthright ‘for the woman I love’.