I went to bed last night convinced that the SNP's extraordinary run of being in the lead in every single Scottish subsample since referendum day had finally been broken. The tally for 'others' in the headline YouGov numbers was down by 2%, making it quite likely that the combined SNP/Plaid Cymru share of the GB-wide vote was down from 5% to 3%. And so it has proved, but incredibly that still leaves the SNP narrowly in the lead in the Scottish subsample, with 33% of the vote to Labour's 30%.
It remains to be seen whether this narrowing of the gap is just an example of the wild fluctuations you can expect when comparing individual subsamples, or whether it's the first sign that the post-referendum surge for the SNP is tailing off just slightly. In the meantime, the SNP's lead has actually increased in this blog's Poll of Polls, which takes account of all subsamples from the last seven days (four from YouGov, one from ComRes, one from Populus and one from Ashcroft).
Scottish voting intentions for the May 2015 UK general election :
SNP 38.4% (-1.5)
Labour 28.1% (-2.2)
Conservatives 17.1% (+1.5)
Liberal Democrats 7.1% (+0.3)
UKIP 4.9% (+0.5)
Greens 2.7% (+0.3)
(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.)