Boris Johnson and Jeremy Corbyn are, on the face of it, about as far apart as it is possible for two political leaders to be. There is no love lost and very little common ground between them. Or perhaps not: people tell me we have the worst prime minister and the worst opposition leader, simultaneously, in living memory.

Whether that is true or not, the similarities could be greater than the differences. Neither has a credible or workable plan for leaving the EU.

The Johnson plan, or non-plan, began with a demand that the EU remove the Irish backstop from the withdrawal agreement or there would be no talks, then decided it was better to talk even without that commitment from the EU, and now