I’ve already hinted at this in a previous post, and I’ve been saying it privately for several weeks: it wouldn’t be a completely wild bet on Alan Johnson being the next Prime Minister.

How? Well, first you have to think the we’re likely to end up with hung parliament in which the Tories and Labour have similar numbers of seats – it may even be after the past week that Labour could have more. Second, you have to assume the Lib Dems gain seats and clearly can form a coalition with either. Again, that’s no longer remote.

On most policy issues the Lib Dems and Labour are clearly closer than either are to the Tories. But, and this is a big but, if Gordon Brown, who is clearly an unpopular PM, has failed to win the election how could the Lib Dems form a coalition that kept him in power? They probably couldn’t, but they could with a new Labour leader – enter Alan Johnson. If one of the prices of a Lab-Lib government was ditching Gordon Brown, who really believes his Cabinet colleagues would rally round to defend him? It wouldn’t be the first time such a coup has happened after an election, maybe not at Westminster but certainly elsewhere.

This process might even start before the Election – it would be appealing to the Lib Dems high command to say that they would not keep Gordon Brown in power, but leave the possibility of a Lib-Lab government open – it would neutralise the Tories “vote Clegg get Brown” attack quite nicely.

At the start of last week this was about as likely as a volcano grounding all air traffic across western Europe….