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For all the talk of the negotiations between Team May and Team Corbyn being "constructive and serious", Labour's leader always seemed somehow more likely to back away from a Brexit compromise with the prime minister than embrace one.

Some of his Labour critics still suspect - though he and his close aides deny it - that he's a lifelong Eurosceptic who would be content with a Brexit that also taints the Conservatives and takes him closer to power.

Mrs May's options are, of course, all but exhausted. Another, final, round of voting to see if any solution gains traction is one of them.

But will Tory rebels suddenly change their minds after three defeats?

Or will Labour MPs, feeling the pressure to deliver Brexit, break ranks and ride to Mrs May's rescue? Some maybe, but enough?

The prime minister has yet to name the date for her departure, but the Tory leadership contest is running at full tilt, as it has, in truth, for some time.

The next leader is more than likely to promise a harder Brexit - maybe with no deal at all. Parliament might oppose that but only the government could, at a single stroke, stop it happening.

So Mrs May's last remaining hope of achieving her "mission impossible" before leaving may just be that heightened fear of a no-deal Brexit changes Tory and Labour minds when the legislation to take the UK out is voted on in early June.

Stubbornness. Duty. A steady diet of faint hope. They'll all feature strongly in Theresa May's soon-to-be-written political epitaph. The chapter about the UK and its future place is the world is still being penned.