Boost for pro-independence campaign as ICM show a No lead only half as big as suggested by YouGov

I was slightly worried earlier this evening when Blair McDougall and Euan McColm eagerly retweeted the news of an impending (and extremely rare) ICM poll on the independence referendum. ICM are of course one of the most credible and evergreen of pollsters, so if they had shown a whopping No lead in line with YouGov, it would have been a cause for concern. But thankfully that hasn't happened, and on balance I'd say that Yes should be the campaign to take most heart from this poll - the figures are roughly equidistant from Panelbase on the one extreme with its one-point Yes lead, and YouGov on the other extreme with its thirty-point No lead.

Should Scotland be an independent country?

Yes 32%
No 49%

The No lead is some five points lower than in the recent TNS-BMRB poll, and a full thirteen points lower than in the recent YouGov poll with its dodgy preamble. ICM also join a clear majority of pollsters in putting active support for Scotland remaining in the UK at less than 50%.

We now essentially have three camps of pollsters - Panelbase with an outright Yes lead, Angus Reid, ICM and TNS-BMRB with middling No leads, and Ipsos-Mori and YouGov with much larger No leads.

Panelbase - Yes lead of 1%
Angus Reid - No lead of 13%
ICM - No lead of 17%
TNS-BMRB - No lead of 22%
Ipsos-Mori - No lead of 28%
YouGov - No lead of 30%

That really ought to lay to rest the suggestions from commentators such as Alex Massie that it's "Panelbase against the field" - if Panelbase are outliers on one end of a very broad spectrum, then YouGov are plainly outliers at the other end.

So what can explain the fact that ICM's No lead is markedly lower than YouGov's? Well, basically, they've shown a degree of professionalism that puts YouGov to shame. They do use a preamble to the referendum question, but it's neutrally-worded, and doesn't cast independence in pejorative terms. They also ask how people think they will vote on the actual referendum date, rather than "tomorrow" (eliminating the risk that voters might assume that they should respond more cautiously to a hypothetical question about "tomorrow", because they don't yet have enough information to vote Yes with confidence). Perhaps most importantly, ICM weight by recalled Holyrood vote, not by recalled Westminster vote as YouGov do. The problem with the latter approach is that it's overwhelmingly likely that some people who voted for the SNP in the 2011 Holyrood landslide will falsely recall that they also voted for the SNP in 2010 - and those disproportionately pro-Yes voters will be wrongly scaled down in the weighted figures as a result.

In a nutshell, it's now very much game on.

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UPDATE : There are also some whispers of another Panelbase poll tonight, although so far I can't find any details.