The most incoherent resignation ever.

Very strange, especially just two days before an election. So what happened? It's like Kremlinology, trying to work out who did what to whom when. 

Let's take one usually reliable approach. Who benefits? It seems unlikely that the Home Secretary herself does, although she may have planned a more Howe-esque departure and been talked down during the day. Perhaps the whips have something even more juicy on her and warned her to shut up, but it seems unlikely. Whatever such a closet skeleton might have been would surely have been lost in the drama of a resignation speech, even a full record of her Blockbuster receipts. The failure to get out and explain herself during the day points makes her an unlikely candidate, I think.

Alex at LabourHome thinks it came from within Downing St, but that covers a multitude of evils. The PM himself clearly doesn't benefit: his shambolic government has taken another step down the apparently ever-descending spiral staircase to electoral hell. I think we can rule him out. 

That leaves Cabinet and the special advisers as the obvious shortlist. Someone who wants her job, perhaps? It seems unlikely at this time of chaos that even one of this crazy crew could be sitting in a bunker trying to work out how to become Home Secretary. 

We're left, I think, with the most likely candidate being someone who wants Gordon's job, and wants to destabilise him as quickly as possible. Johnson, Milliband, or Harman, those would be the obvious guesses, and Johnson would appear to benefit most as the heir apparent. It's a bit thin even by New Labour Kremlinology standards, but it's the best I've got. 

If it was him, or indeed if it was any of the Cabinet, there'd have to be an ally in Downing St for them to give a little plausible deniability.