Disaster for Tories as up-to-date YouGov poll unexpectedly shows their lead dropping even further

It's that time again, folks.

*puts on Canadian accent*

It's another terrrrr-ible night for the Conservative party.

Britain-wide voting intentions (YouGov) :

Conservatives 43% (-1)
Labour 38% (+3)
Liberal Democrats 10% (+1)
SNP / Plaid Cymru 5% (n/c)
UKIP 4% (+1)
Greens 1% (-1)

I've already had to hurriedly update this blogpost, because YouGov have broken the habit of a lifetime by getting their datasets out straight away, which means we don't have to wait until the morning to learn the SNP's vote share.  The good news is that the party appear to be holding firm, although there's no sign of any additional progress in the Scottish subsample - the SNP lead the Tories by 41% to 30%, which is pretty similar to the most recent full-scale Scottish poll from YouGov.  But of course individual subsamples are not especially reliable - it's perfectly possible that this one is underestimating the SNP lead, and that the GB-wide Tory slump is being replicated in these parts.  And it's certainly very interesting to learn that it's even possible for Labour to reach a heady 38% of the GB vote without a major recovery in the Scottish subsample (although admittedly their 22% showing is somewhat better than their recent average).

The fieldwork for this poll took place yesterday and today, which means not only that it was entirely after the tragedy in Manchester, but also that it was entirely after the Prime Minister's announcement that the UK's threat level had been raised to 'critical' - which I thought was the moment that might have the really significant political effect by putting security matters (a traditional area of Tory strength) at the forefront of voters' minds.  YouGov have pointed to some internal polling as evidence that the situation was even worse for Theresa May on Monday, implying that the events of the last few days have indeed helped her to recover from a low that we weren't even aware of - but even if that's true, it looks like the recovery must be extremely modest.  It appears that we may have a tendency to significantly overestimate the effect of sudden shocks on voting intentions - like many others, I expected the reaction to the Jo Cox tragedy last year to boost the Remain vote, and perhaps it did, but not by a decisive amount.

As always with a single poll showing something truly out of the ordinary, we need to remember that the further narrowing of the Tory lead could just be an illusion caused by sampling variation.  But what this does mean is that it's pretty unlikely that the Tories are in a better position now than they were immediately after their manifesto launch, when it appears their lead may have slumped to single figures.  (The only polling firm taking issue with that is ICM, who put the lead at 14 points.)  It looks, therefore, as if Monday's U-turn on social care did not have the desired effect, and may even have made things worse for the Tories - at least in the short-term.

To answer the question a lot of people are asking : yes, if there's a uniform swing between Tory and Labour, and if the Lib Dems and SNP are resilient in seats they're defending, this poll takes us firmly into hung parliament territory.  The trouble is that the Brexit factor means there almost certainly isn't going to be anything even close to a uniform swing, meaning it's impossible to know for sure whether a 5% Tory lead would translate into a hung parliament or a small overall Tory majority.  But at the very least it would put the Tory majority at severe risk.

Of course the million dollar question is whether the polls are even accurate.  It would be a mistake to jump to the conclusion that the polls must be underestimating the Tory lead by roughly as much as they did last time, because methodology has been changed since then in the hope of avoiding any repeat.  Nevertheless, Matt Singh is gaining a lot of publicity for his prediction that the Tories will once again significantly out-perform the polls.  I must say I was a little underwhelmed by his reasoning - he's certainly on solid ground in suggesting that leadership ratings are predictive of election results, but I fear he may be placing too much emphasis on the sharp difference between the outcomes of May local elections and June general elections in 1983 and 1987.  It's possible there were 'era-specific' explanations for that phenomenon (such as the existence of the SDP-Liberal Alliance).  There's no reason to automatically assume that because something has happened twice in the relatively distant past, it's bound to happen a third time.

One problem the Tories have now got is that if they're in a bit of a hole, they can't really dig their way out of it by going after Jeremy Corbyn quite as brutally as they probably intended to until recently.  National campaigning will get underway again tomorrow, but all parties (with the possible exception of UKIP) will know that anything too nasty from them could backfire badly given the current public mood.

And a comforting thought to finish with - if this poll is close to being right, it reflects the state of public opinion at a time when the election was already underway.  A great many postal votes have already been cast.