Elections always prove that politics is a branch of the humanities rather than the sciences. The noisy number-crunchers led the campaign and missed all the popular emotions. As the strategist David Axelrod said, the only thing wrong with the polls was the numbers. Fresh from their failing obsession with arithmetic, British pundits who rarely contemplate America without falling for it will now regale us with the spurious lessons of the Donald. That said, there is one way in which the US election came down to numbers — and it carries a lesson for the parties of the left.

Listen carefully and, in the noise, there is a signal for left-of-centre parties in the Trump victory. Bill Clinton won elections, and his model served for Tony