Boris Johnson concludes his Churchill biography with splutters against historians who insist the “story of humanity is not the story of great men and shining deeds”. The story of Winston Churchill, he cries, “is a pretty withering retort to all that malarkey. He and he alone made the difference.”

The story of Boris Johnson withers too. He is shrivelling Britain: making it cramped, poor and irrelevant. Modern historians may sniff at the 19th-century notion that “the history of what man has accomplished in this world, is at bottom the History of the Great Men” to use Thomas Carlyle’s words. The rest of us should not be so complacent and register the capacity of catastrophic men and women to change the world for the worse.

In his classic study On the Psychology of Military Incompetence, Norman Dixon analysed British generals who had led their men to pointless deaths from Crimea to Arnhem. How familiar his diagnosis feels. Dixon identified “overweening ambition dedicated to one goal – self-advancement” as a persistent fault; and that sounds familiar. Catastrophic men equated “war with sport”, he continued, and one thinks of Theresa May’s warning in 2016 that “politics isn’t a game.”