If the LibDems are not be entirely naive in their acceptance of the Conservative pledge to allow a referendum on the AV system, they must get to work on the task of explaining what the proportional representation alternatives really are.

The one outstanding mystery for me from the ToryDem negotiations is that both sides wound up discussing AV as the ‘PR’ system to be tested. The inverted commas there represent nothing more than reality: for AV is NOT a PR voting system at all. Not only that: were it to be adopted, the Tories would be consigned to opposition forever.

The obvious extrapolation is that the LibDems grasped at this as the best way to justify a pragmatic deal: power is on offer, therefore we should take it. But equally, one would have to conclude that the Tories were either mad to give way on the AV referendum – or certain that it would never be acceptable to the electorate.

PR systems are notoriously difficult to sell. The best system – STV – requires considerable electoral reorganisation, and a major investment in the infrastructure of voting. Having said that, the ‘creaking’ nature of our electoral system was revealed for all to see in the General Election; so if spending on it is necessary anyway, why not reform it in terms of real PR at the same time?

AV could very quickly become one of those learning curves up which voters clamber…and, having done so, decide that the mountain wasn’t worth climbing in the first place. That would suit the Tories very nicely thank you….but it would not be a fair crack of the whip for PR.

This is one of those cases where perhaps both sides need to withdraw and consider. A proper STV system would give the LibDems their fairer votes – and be as fair to the Tories as it would be to Labour. No Party has anything to fear from it. And the coalition could justifiably present itself as the truly progressive front that made it happen.

My own instinct is that, in the face of the coming crisis, the whole issue will retreat to the back-burner. I don’t mind that – just so long as nobody turns the gas off.