Today's update of the Poll of Polls is based on ten Scottish subsamples from Britain-wide polls - four from YouGov, two from Populus, one from ICM, one from TNS-BMRB, one from Ashcroft and one from ComRes. It has to be said that some of the last week's subsamples are as mad as a bucket of frogs, ranging between these two extremes...
ComRes : SNP 59%, Labour 13%, Conservatives 11%, Greens 6%, UKIP 5%, Liberal Democrats 5%
TNS-BMRB : Conservatives 34%, SNP 24%, Labour 23%, Greens 6%, UKIP 5%, Liberal Democrats 5%
OK, freakish results can happen in small subsamples, but this is in fact the second time since the referendum that TNS have had the Tories ahead of the SNP. When taken together with the fact that the full-scale Scottish poll from TNS also produced a result well out-of-step with other firms, you do start to wonder if there's an issue with their methodology.
However, put all the discordant results from the various firms together, and this is what you're left with...
Scottish voting intentions for the May 2015 UK general election :
SNP 43.8% (-0.8)
Labour 23.0% (-4.0)
Conservatives 17.8% (+0.1)
Liberal Democrats 7.0% (+3.6)
UKIP 4.5% (+1.5)
Greens 2.9% (-0.5)
(The Poll of Polls uses the Scottish subsamples from all GB-wide polls that have been conducted entirely within the last seven days and for which datasets have been provided, and also all full-scale Scottish polls that have been conducted at least partly within the last seven days. Full-scale polls are given ten times the weighting of subsamples.)