Chris

Their calculation is that the EU won't grant an extension unless there's some prospect of a deal emerging that parliament will back. Any further signs of intransigence in parliament feeds into that view. They may also be calculating that there is a point at which Teresa May will go for No Deal in preference to a drawn out process that sooner or later is going to end in either a referendum, or a general election, or both.

I'm not certain they're thinking straight, but I'm by no means certain anybody is. Bercow, for all his supposed impartiality, clearly thinks that he's assisting the EU in granting a long extension in order to allow a totally different, softer, Brexit to be negotiated. He's dispensed with convention often enough over the last month, it simply isn't credible for him to start using it as an excuse for blocking Government business now, especially on an issue as important as this.