Robert Peston: Is a Brexit delay or a general election more dangerous for Boris Johnson?

Will Boris Johnson shelve his October 31 do-or-die pledge in next 24 hours? He is implying he won't, but in fact he hasn't quite said that today.

He's said he won't allow "months" of delay. So if he loses the vote on his timetable today, he'll face a choice of agreeing with Labour a couple of extra weeks of debate, or losing the bill altogether.

If he loses the bill, he can probably have a general election with a one-line bill for one.

So the choice is between trying to get a Brexit deal with a short delay, but with the associated humiliation of missing the October 31 date, or campaigning in a December general election on a platform of delivering his deal if he regains power.

All this is predicated on reasonable assumption that Brussels will give a delay either to pass the deal or for a general election.

So tonight the prime minister has to work out what is least risky: holding a general election on the platform of his deal, or agreeing that Brexit can't happen for a few additional weeks.

The risk of the election is he loses power. The risk of agreeing a delay is he loses Brexit or a Brexit he regards as being worth the name - it's a tough choice.

But he knows he cannot govern in any meaningful sense unless and until there is a general election.

And he may feel that there will never be a better manifesto pledge for an election than that he'll deliver his negotiated Brexit deal if he wins.