Cripes! We might win. What on earth are we going to do then? No, that was not the inimitable Boris Johnson contemplating this week’s mayoral showdown with Ken Livingstone. It was one of David Cameron’s shadow team on the dawning prospect of a Conservative return to government.

All right, I admit my Tory friend did not actually say “cripes”. Mr Johnson, thankfully, is unique in his studied reverence for the playground idiom of Greyfriars School. But the shared sense of shock is real. Mr Johnson, I would guess, wakes up in a cold sweat at the idea of running one of the world’s great cities. Likewise, smart Tories shiver at the thought that within a year or two their party may be governing the country.