Johnson + PR + Lib Dems = salvation?

An interesting alliance of right wing and left wing columnists speculating today on the latest scheme to save New Labour's ass - e.g. Polly Toynbee in the Guardian and Peter Oborne in the Mail.

The plot, roughly speaking, goes like this:

1. Alan Johnson becomes Prime Minister.
2. He introduces proportional representation.
3. He calls a general election.
4. The Tories fail to secure 50% of the seats.
5. Labour go into a coalition with the Liberal Democrats.

It's an interesting theory. Although I have previously suggested that Alan Johnson would be seen as not young or fresh enough if he attempted to run for the leadership after an election, before an election might be a different matter. There are several ways in which it could fall down, though. For instance:

• How, precisely, does Alan Johnson stage a coup to get rid of Brown? The most obvious scenario is if the whole cabinet - or almost the whole cabinet excepting Ed Balls - just tell Brown, perhaps following the Euro election results announcement on Monday 8th June, that his time is up, and he either resigns or they will back Johnson as a candidate in a leadership campaign. That will take a lot of coordination and balls - not Ed Balls but real balls - which have been in short supply recently (and indeed perhaps always).
• Could Johnson get PR through the house of Commons with the current composition of MPs? Presumably all the Tories would vote against, and all the Lib Dems would vote in favour. Could enough Labour MPs be pushed through the lobby to get it through? Maybe.
• When the election is held under the new system, can Labour and the Lib Dems poll enough between them to command a majority of MPs? With Labour on approximately 20% (on a good day) and the Lib Dems on 15% (on a good day), this looks unlikely. But then again, the Tories are polling at around 40% rather than above 50%. So, assuming that minor parties like UKIP and the Greens would improve their support under PR, we might be looking at some very weird coalitions emerging after the election. Which would certainly be interesting, but perhaps not what Labour had originally intended. A Tory-Lib Dem coalition might be the most stable outcome - and fear of that might stop Labour from introducing the reform in the first place.

There would inevitably be huge accusations of opportunism confronting Johnson, or anyone else who tried to implement this kind of scheme. Having said that, this could be the best possible time to do it. Johnson could say to his critics: (a) everybody accepts that fundamental reform is needed, and (b) we need a general election asap - and as soon as we've changed the voting system, you'll have it. My guess is that once we've moved away from the lunacy that is first past the post, we'll never go back to it.

The poll just published in the Telegraph reinforces the feeling that change could be near. With Labour down to 22% in general election voting intentions (below the Lib dems for the first time since 1987), and 19% in the Euro voting intentions, Johnson and co. may have a relatively easy time of persuading Team Brown that the game is up come June 8th. But I'm still rather sceptical that Gordon will Go Quietly.