Unnoted in my diary were locations even more spectacular. The opening concert was shot in the Double Cube room at Wilton, where the hand-bell ringers give their somnolent rendering of ‘Greensleeves’ (‘Fascinating stuff!’ says the King) in front of the sumptuous backcloth of Van Dyck’s portrait of the Earl of Pembroke and his family. The Prince of Wales’s lodgings were at Wilton and the Royal Naval College at Greenwich, where Wren’s Painted Hall was the setting for the second concert, when the King runs amok. The long gallery in which George III sees Pitt at the start of the film and its close, and down which Pitt bows himself endlessly out, is at Syon House, as was the Prince of Wales’s breakfast room. Arundel Castle doubled for Windsor. Medievalised around the same time, Arundel shares many of the features of its more familiar counterpart, though catch either of them on a wet day and they look like long-stay institutions for the criminally insane.

The title of the stage play is The Madness of George III and of the film, The Madness of King George. This was a marketing decision; the American backers somewhat shamefacedly explained that the audience might think, seeing The Madness of George III, that they had missed out on The Madness of George and The Madness of George II, a survey having apparently shown that there were many moviegoers who came away from Kenneth Branagh’s film of Henry V wishing they had seen its four predecessors. Where this leaves The Third Man (or The Second Mrs Tanqueray) I’m not sure.

Many of the actors and actresses in the stage play took part in the film, though not always in the same roles. Nigel Hawthorne remained George III and Julian Wadham Pitt, and two of the King’s doctors and two of his pages were the same on stage and on film. Even when this continuity wasn’t possible there was often a niche in the film for actors who had been displaced: Iain Mitchell, who played Sheridan on the stage, is the pig farmer (with terrible teeth) at the start of the film. Helen Mirren played Queen Charlotte, but Selina Cadell, who had played the Queen in the second National Theatre production, became Mrs Cordwell, a patient in Dr Willis’s Lincolnshire asylum who lost her wits when her sea-captain husband was drowned off the Goodwin Sands. The scene in the asylum was originally much longer, with the patients due to be played by some of our leading stage directors, including Richard Eyre, Sam Mendes and Declan Donnellan. The directors proved, of course, much more temperamental and hard to please than actors and one by one got cold feet, leaving only Stephen Daldry gamely plying a lonely sickle. Alas for his loyalty, his scene was one of the earliest cuts.