Although the recent Panelbase poll showed a two-point drop in support for independence, that was simply a reversion to the mean. The Yes vote was 47%, which is very typical of what Panelbase have been reporting since the referendum. Today's YouGov poll also shows a 2% drop in the Yes vote, but this is something different, because it sees support for independence slipping to 45%, which is outside YouGov's normal range. Until we see corroboration of that trend from another pollster, the jury will be out on whether public opinion has really shifted, or whether this is a one-off finding. There is nothing obviously suspicious in the datasets, but remember that one poll in every twenty is expected to be an outright 'rogue poll', ie. less accurate than the standard margin of error of 3% in either direction. Considerably more than one poll in twenty will be out by 2% or more, so this could just be an extreme example of margin of error 'noise'. Time will tell.
And the big disparity between YouGov-style online polling and 'real world' polling (telephone and face-to-face) should also be borne in mind. The only two real world polls on independence since the referendum have shown a clear Yes lead, so even if there has been some recent slippage, it's still perfectly possible that Yes are ahead.
YouGov also asked the EU referendum question, and found overwhelming and growing Scottish support for remaining in the EU - on the very same day that a Britain-wide YouGov poll showed the Leave campaign opening up a potentially significant 9% lead.
Should the United Kingdom remain a member of the European Union or leave the European Union?
Remain 55% (+4)
Leave 28% (-3)
That Remain lead is even more emphatic than suggested by the Scottish subsample of the Britain-wide poll (although admittedly the comparison is not completely exact, because part of the fieldwork for the Scottish poll preceded Cameron's failure to secure a substantive deal). The Leave vote is also a whopping 17 points lower than in Britain as a whole, so with the best will in the world, it's very difficult to see how any overall Leave victory isn't going to be coupled with some kind of Remain win in Scotland, thus providing a casus belli for a second independence referendum.
* * *
SCOT GOES POP INDEPENDENCE POLL OF POLLS
This update of the independence Poll of Polls takes into account two new polls (Panelbase and YouGov), so the changes are a bit less glacial than normal. As you'd expect, the run of two successive updates showing an exact 50/50 split has been broken, but the state of play remains very tight.
MEAN AVERAGE (excluding Don't Knows) :
Yes 49.2% (-0.8)
No 50.8% (+0.8)
MEAN AVERAGE (not excluding Don't Knows) :
Yes 45.5% (-0.8)
No 47.0% (+0.7)
MEDIAN AVERAGE (excluding Don't Knows) :
Yes 47.9% (-1.3)
No 52.1% (+1.3)
(The Poll of Polls is based on a rolling average of the most recent poll from each of the firms that have polled on independence since the referendum, and that adhere to British Polling Council rules. At present, there are six - YouGov, TNS, Survation, Panelbase, Ipsos-Mori and ICM. Whenever a new poll is published, it replaces the last poll from the same company in the sample.)