Yes vote soars to yet another record high among definite voters in new poll from traditionally No-friendly firm TNS-BMRB

It's been a bruising few days for Blair McDougall and the other Abominable No-Men, as their hopes of a post-debate polling bounce have receded.  We now have a second poll that was partly conducted after the debate, and the pattern is uncannily similar to the first one - the No lead has actually fallen among definite voters.  And in this case, it's fallen to its lowest level of the campaign so far in any poll from the traditionally No-friendly firm TNS-BMRB.

Should Scotland be an independent country? (Definite voters only)

Yes 38% (+1)
No 46% (n/c)

Although that's only a 1% increase in the Yes vote share, it's worth remembering that the 37% vote recorded in last month's poll was 2% higher than it had been in any previous TNS poll - or to put it another way, tonight's poll has the Yes vote 3% higher than in any TNS poll prior to July.  A rough calculation suggests that with Don't Knows excluded the position is likely to be Yes 45% (n/c), No 55% (n/c), although there's an outside chance that it might be Yes 46% (+1), No 54% (-1), which would also be a new record.  We'll find out when the datasets are published, presumably tomorrow.

On the headline figures that cover the whole sample regardless of likelihood to vote (they even include people who say they are absolutely certain not to vote!) there has been a predictable reversion to the mean since the last poll which saw the No lead slump to a record low by a huge margin.  The bad news for the No campaign is that while tonight's figures may not be the worst for them in a TNS poll, they're the second worst.  Last month's poll was the first time in the campaign that Yes had been higher than 41% in a TNS poll after Don't Knows were stripped out, and tonight is the second.  That makes it very difficult to argue that Yes haven't made further progress since the spring, unless there have been some highly coincidental margin of error effects in both of the last two polls.

Should Scotland be an independent country? (Whole sample with Don't Knows excluded)

Yes 42% (-2)
No 58% (+2)

With Don't Knows taken into account, Yes remain on 32%, which is their record high for the campaign - prior to last month's poll they had never been higher than 30% (or at least not since TNS introduced an enormous methodological change).

When the datasets are released, the first calculation I'll be making is voting intentions with the small number of definite non-voters stripped out - in both of the last two TNS polls that in itself was sufficient to increase the Yes vote by the best part of 1%.  And that gives a clue as to why the figures for definite voters only (which TNS are increasingly giving parity of esteem to) may be the more meaningful ones - they equate to a turnout in the low 70s, which is perfectly plausible.  If you think that the turnout is more likely to be around the 80% mark (or a bit higher), then the relevant figures will be for those who say they are very likely or certain to vote, and we won't find out what those are until tomorrow - although it's reasonable to assume that they'll be more favourable for Yes than the numbers from the whole sample.

As I always point out, good results for Yes in polls from TNS and Ipsos-Mori are worth more than good results from other pollsters, because those two are the only firms that don't rely on volunteer online panels for their referendum polling, and that actually seek out a sample in the 'real world'.  It's hugely encouraging that both are now showing Yes at a record high for the campaign among definite voters (42.5% in the case of Ipsos-Mori, 45% or 46% in the case of TNS) as we enter the crucial last few weeks.

And what does the TNS poll tell us about the post-debate polling landscape more generally?  It slightly increases the likelihood that the Survation poll showing an unusually high No lead was an outlier caused by random sampling variation - but the emphasis is on the word 'slightly', because what we really need to be sure is another poll that was entirely conducted after the debate, rather than only partly.

Final thought - as far as we know, TNS haven't yet joined the new orthodoxy of weighting by country of birth.  That may not be such a huge issue for them, because a face-to-face pollster ought to find it easier than an online pollster to put together a representative sample - but it would still be a very wise idea to weight by country of birth to be on the safe side, because it's such a strong predictor of referendum vote.

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SCOT GOES POP POLL OF POLLS

To state the bleedin' obvious, the only reason this update of the Poll of Polls shows a slight increase in the No lead is that TNS are represented in the sample by their headline figures - if they were represented by the numbers for definite voters (as is the case for Ipsos-Mori), the No lead would have fallen back again.

MEAN AVERAGE (excluding Don't Knows) :

Yes 42.4% (-0.4)
No 57.6% (+0.4)

MEAN AVERAGE (not excluding Don't Knows) :

Yes 36.5% (n/c)
No 49.5% (+0.7)

MEDIAN AVERAGE (excluding Don't Knows) :

Yes 42.5% (-0.3)
No 57.5% (+0.3)

(The Poll of Polls is based on a rolling average of the most recent poll from each of the pollsters that have been active in the referendum campaign since September 2013, and that adhere to British Polling Council rules. At present, there are six - YouGov, TNS-BMRB, Survation, Panelbase, Ipsos-Mori and ICM. Whenever a new poll is published, it replaces the last poll from the same company in the sample. Changes in the Poll of Polls are generally glacial in nature due to the fact that only a small portion of the sample is updated each time.)