Will May or Corbyn fall first?

Theresa May and Jeremy Corbyn are both on that Italian Job bus dangling over the cliff, with gold bars at one end and survival at the other. May wants to pursue her Chequers Brexit plan, even though doing so is alienating up to half her own MPs, True Brexiters and some erstwhile Remainers like Nick Boles (though, in truth, he has always been more Govean – or the agriculture secretary’s representative on earth – than europhile). According to her senior colleagues, May will not turn back – even though continuing to negotiate with the EU on her Brexit scheme would deliver a deal even less palatable to the Davises and Johnsons than the White Paper policies she wrote and they used as reason to quit her cabinet (if there is a deal at all; the damning overnight verdict of the EU’s chief negotiator Barnier augurs ill for May’s plan).

Nor is it only her position as PM that could tumble over the precipice, if her Brexity critics make good on their threat to launch a coup.