What, if anything, have dictators over the centuries had in common?

Big Caesars and Little Caesars is an entertaining jumble with no obvious beginning, middle, end, or indeed argument. But there is an intriguing book buried underneath it which asks more or less this: where does Boris Johnson stand in the historical procession of would-be strongmen or, as Ferdinand Mount calls them, ‘Caesars’? How successful was Johnson’s attempt – overshadowed by the Brexit noise, his personal scandals and his Bertie Wooster act – to turn Britain into a more authoritarian state?

Mount, now 84, comes at this from a long Tory past that in recent years he has seemed to disown. Though he spent most of his career as a journalist and novelist, he was, also, incongruously, head of Margaret Thatcher’s No.10 Policy Unit in 1982-83, just as she began remaking the country. He described this stint in his 2009 memoir Cold Cream: My Early Life and Other Mistakes (a much better book than the new one).