The conventional wisdom that the 'No' side are coasting to victory in the AV referendum has been blown apart by a new ICM survey that shows 'Yes' ahead by 35% to 22%. Whether or not these figures are any more credible than the YouGov ones showing the opposite picture, one thing that does seem eminently plausible is the huge number of 'don't knows' at this stage on an issue about which there has been very little publicity so far. The referendum is therefore wide open and out there to be won by either side.
My suspicion is that, with the current toxicity of Nick Clegg's party, the more non-Liberal Democrats become openly associated with the Yes campaign (and do so for their own reasons) the greater the chances of success. It will be fatal for it to be seen as a Lib Dem baby. I also firmly believe it's vital that Yes campaigners don't give in to the temptation to say that AV must be allowed to 'bed in' before any further changes to the electoral system are considered - the danger that supporters of PR will feel uninspired by the prospect of this timid reform far outweighs the need to reassure others who might fear they are voting for the thin end of the wedge. The latter group are scarcely natural Yes voters in any case.
Furthermore, establishing a narrative well in advance of polling day that (whether Clegg and Cameron like it or not) a 'Yes' is a vote for the first small step in a process of electoral reform will make it much easier for PR supporters to build on any victory afterwards. So it's the right strategy twice over.