I imagine Gordon Brown had wielded the knife and told him his position was untenable and that if he didn't go the government would give time to a no confidence debate. But that's pure guesswork. No doubt the truth will out over the coming hours.
It is not yet clear what his timetable for departure is. I detect that the House is in no mood for him to hang around until the Summer recess or even until the election. If he tries to, there will be uproar this afternoon. It will take a little while for an election to be held to elect his successor and I imagine everyone will be happy for him to chair proceedings until then.
The news broke on Scottish Television at 10.32am, although the Evening Standard's Paul Waugh is laying claim to have broken it two minutes before them.
I almost hesitate to remind you of my words last Friday, which got such ridicule from many of the commenters...
By the end of this month, Michael Martin will no longer be Speaker. Indeed, I'd almost be willing to bet that he will have stepped down by the end of next week.I must admit I am not the best soothsayer in the world, but at least I got this one right!
UPDATE: The BBC are reporting that Michael Martin won't be going "immediately". Hmmm.