A few weeks ago I warned that the Prime Minister might soon experience the wrath of a wounded chipmunk. I could never have predicted that Hazel Blears would resign from the Cabinet the day before an important set of elections. Her departure is entirely understandable, as she has experienced weeks of briefings against her. Over the last 12 hours Downing Street have been briefing the media that it was Blears who leaked the fact that Jacqui Smith would be leaving. Her patience snapped, and she told Brown that she'd had enough. Her resignation statement was notable for its lack of a single mention of Gordon Brown or the "achievements" of his government, which is the normal thing in these matters.

Readers know that I have a lot of time for Hazel Blears. I do think that she has been one of the more talented Cabinet Ministers, not that she has had a lot of competition for that accolade. But the most important thing is that many of her colleagues underestimate her.

I suspect that she may well make a resignation speech in the Commons next week. Could she really turn out to be Geoffrey Howe reincarnated? Analogies with the events of November 1990 can be overdone, but there's another one too - remember how Margaret Thatcher went to France in the middle of her troubles? Guess who's off to France at the weekend. John Biffen said her departure was like standing in front of a Paris underground map and watching all the lights go on.

I had a text from a Labour MP this morning which said: "Right, that's it. Enough". There are two things which will determine Gordon Brown's future: whether there are any more resignations, and the results of the County Council and European elections. I gather there is a letter of no confidence doing the rounds of Labour MPs today. The rumour is that 40 MPs have signed up to it already. It needs 72 before events take on a momentum of their own.

Let's scroll forward. If Brown goes - and I now think that is possible, if not probable - would the British public (and more importantly the media) stomach a second unelected Prime Minister in a row? Constitutionally, there is no reason the government is forced to hold an election in these circumstances, but politically it might be unavoidable. I don't think a new prime minister could get away with simply saying that the election will be in May 2010.