Equally unlikely is Prince Charles asking Major what happened during his private audience. It also doesn’t ring true from everything we know of the Queen. It is a very long time since any monarch dared to speak so peremptorily to any first minister, probably not since her Stuart predecessors in the 17th century. Imelda Staunton, more Vera Drake than Elizabeth II, tells him the vessel is “a floating, sea-going expression of me” and demands that the government does as she asks “without question”.

The poor man also has to sit through a preposterous monologue from the Queen about the government paying for the refurbishment of the royal yacht (which the Major government certainly considered for a time, according to his memoirs). He didn’t conceal his past but celebrated it – and no one ever confused him with a socialist. It’s a wonder Major doesn’t reply: “Cor blimey, guv – you got me bang to rights!” Of course that little exposition is intended for the US audience, who may not know Brixton from Balmoral, but we have Major’s assertion that no such scene ever happened, and I think we can take it that he’s right. Thus Prince Charles in the scene where he hints to the prime minister, John Major, about persuading the Queen to abdicate says: “One might have expected coming from Brixton, a multicultural working-class part of London, you might have concealed your past in order to fit in with the Tories, or to have a more socialist viewpoint.” The characters go round telling one another what they must already know. We correspondents often refer to the royal soap opera, but the conversations in this are straight out of a poor one (though the sets are too solid to sway). Elizabeth Debicki as Princess Diana, with Dominic West’s Prince Charles: ‘Her portrayal as wilful and paranoid seems about right.’ Photograph: Keith Bernstein/APīut it’s the dialogue and the situations that clunk.

Lawson bates