For the first time in 2015, the SNP and Plaid Cymru have reached 5% of the GB-wide vote in a YouGov daily poll...
Britain-wide voting intentions (YouGov, 7th-8th January) :
Conservatives 33% (+1)
Labour 33% (n/c)
UKIP 13% (-2)
Liberal Democrats 8% (+1)
Greens 7% (n/c)
SNP/Plaid Cymru 5% (+1)
And the Scottish subsample figures couldn't be more different from yesterday's : SNP 46%, Labour 24%, Conservatives 17%, Liberal Democrats 6%, UKIP 5%, Greens 2%. We're in for greater day-to-day volatility now that YouGov are relying on much smaller Scottish samples, and the fluctuations this week are a good example of what to expect on a regular basis - the SNP's lead has varied from 6 points to 22. (In fact, the volatility could well prove to be a lot worse than that.)
I must say I'm more confused than ever about the exact nature of YouGov's methodological change. In his first clarification, Anthony Wells left the distinct impression that the only thing that had changed about the Scottish sampling was that they were sending out fewer invitations. But yesterday he suggested that they are now using Scotland-specific target figures, just as they would for full-scale Scottish polls. If that's true, I can't make any sense of the fact that SNP identifiers are still fairly obviously being downweighted according to Westminster-centric targets, rather than the political weighting being done by 2011 vote recall, as would happen in full-scale polls. It may be that the Scottish sample is now demographically representative in a way that it hasn't been before, but if so, that good work is being largely undone by distorted party ID weightings, and by the smaller number of respondents.