In general the Prince of Wales is more forceful and more of a villain in the film than he was on the stage or in life. There’s no doubt that he was anxious to be made Regent, but he was more careful of appearances than I have made him and was more governed too by that fellow-feeling all royals have for each other. The Prince of Wales, for instance, was understandably sensitive to any suggestion, particularly in the press, that his father was mad. For a subject to remark on the King’s state of mind seemed to the Prince insolent and intolerable. Or sometimes seemed to him insolent and intolerable. For the Prince himself to make such a suggestion (and to make jokes on the subject) was permissible and permissible too, a lot of the time, for his cronies. But suddenly they would find they had gone too far, the Prince would get on his high royal horse again and his friends would have to mind their p’s and q’s for a bit. It’s a characteristic of royalty that one minute they are happy to masquerade as ordinary persons and the next they demand to be treated as a race apart. Like the rest of us, I suppose, they just want things both ways, but this ‘Now you “Sir” me, now you don’t’ must make intimacy with royalty a little wearing, and friendship with them must always involve an element of Grandmother’s Footsteps. Like Fitzroy, courtiers must learn to be pretty sure-footed, with little hope of ever being ‘natural’, the ideal somewhere between those who can’t forget the royals’ highness (and so are stilted) and those who forget it altogether (and so are cheeky).

These reservations apart, I found I was less sceptical about the monarchy as an institution than my colleagues on the production team, partly because (and slightly to my surprise) I was older than most of them and more set in my ways. Certainly I’m no republican and find nothing particularly extraordinary in the difficulties and embarrassments of the present Prince of Wales. It’s a role, after all, which has seldom been satisfactorily filled; I suppose George V was good enough at it, but he was a dull man who was heir-apparent for a relatively short time, acceding to the position on the unexpected death of his much less suitable elder brother for whom no one had a good word, some even identifying him with Jack the Ripper. (Even the Sun hasn’t managed to insinuate that Prince Charles is a serial killer.) But when the Prince of Wales in the film says that to be heir to the throne is not a position, it is a predicament, it’s meant to be both a cry from the heart and a statement of an obvious truth.