Bit of a hostage to fortune here, but since I correctly predicted the departure of Charles Kennedy from that party, erm the Demerol Limocrats, I think, way before he actually went, I think I have form you can follow with confidence.
When a story like the health of the PM gets into the MSM the first question you ask is, "in whose interests is it that this story is made public?" Since the health of Gordon Brown and his medical details are personal and private, this must have been made public with the approval of Number 10. I see the deft hand of Alastair Campbell all over this.
Be in no doubt folks. GB is leaving the building. Before the election. Why? Because he has always run away. Because he is incapable of running against anybody else. Because he is a coward. He knows he is going to lose the election for Labour. He cannot face that because he is in denial. This is his way out. And he will take it.
Addendum/Update: I found the original Charlie Kennedy prediction, made on Thursday 15th December. As late as 18th of December, the Liberal Leader was denying everything:
"on 18 December 2005 when asked "Has it been a battle to stay off the booze, have you had to have medical support in any way at all?" Kennedy replied "No, no, no, that is not the case.." (ring any bells?)
Kennedy resigned on 7th January, 2006.
Thinking about it - it's a bullet-proof way to go, after all the opposition can't kick a man when he goes on health grounds can they? Labour will pick up a few points with the exposure that a leadership election gives to a party, the new man will be seen as a new broom, and many will want to "give him a chance". The new leader calls an election and, bingo, he can spout a brand new set of lies. Perfect. Well done Alastair.