Two years ago, Boris Johnson had British politics at his feet. He had won the largest Tory majority since Thatcher, broken the Brexit deadlock and forged a new electoral coalition.

Yet Johnson now finds himself on the verge of a vote of no confidence by his own MPs, and this turnaround hasn’t been triggered by some great ideological divide: this isn’t like old Tory arguments over imperial preference, the poll tax or Europe but by Johnson’s own behaviour and the way No.