We have a bumper crop of opinion polls today – as well as the regular twice-weekly Populus poll, weekly Ashcroft poll there is the first of a series of monthly Survation polls for the Mirror. Still to come tonight is the daily YouGov poll and a ComRes telephone phone for the Indy, both due at 10pm-ish.

The three have been published so far are:

Populus – CON 34%, LAB 35%, LDEM 9%, UKIP 13%, GRN 6% (tabs)
Ashcroft – CON 32%, LAB 32%, LDEM 6%, UKIP 15%, GRN 9% (tabs)
Survation/Mirror – CON 31%, LAB 30%, LDEM 7%, UKIP 23%, GRN 3% (tabs)

All three polls have Labour and the Conservatives within one point of each other – Populus with Labour one ahead, Survation with the Tories one ahead, Ashcroft with them equal. There is more difference between the reported levels of support for the Greens and UKIP – Survation traditionally give UKIP their highest levels of support and have them up on 23% (this is clearly not just because of prompting, given ComRes, YouGov and Ashcroft also now include UKIP in their main prompt), in contrast Populus have UKIP on 13%. Green support is up at 9% in Ashcroft’s poll, but only at 3% in Survation’s. Unlike ComRes’s online polls (harsh turnout filtering) and Populus’s polls (disadvantageous weighting) there is nothing particularly unusual about Survation’s methods that would explain the low Green vote.

I will update later with the ComRes and YouGov polls.

UPDATE: The monthly ComRes telephone poll for the Independent is out and has topline figures of CON 31%(+2), LAB 30%(-2), LDEM 8%(-4), UKIP 17%(+1), GRN 7%(+2) (tabs). It’s the first time that ComRes have shown a Tory lead in their telephone polls since 2011, and a fourth poll today to show the two main parties within a single point of each other. YouGov is still to come…

UPDATE2: The last of today’s five GB polls, YouGov’s daily poll for the Sun has topline figures of CON 34%, LAB 33%, LD 6%, UKIP 15%, GRN 7%. That’s five polls today, all showing Labour and the Conservatives within 1 point of each other. As we hit the hundred days to go mark we have the closest possible race in terms of vote share, if not necessarily in seats.

Tony Twyman, who died last year, was the man behind much of the mechanics of TV and radio viewing figures, most notably as technical advisor for BARB viewing figures. In broader market research he is more widely known for coining Twyman’s Law – “Any figure that looks interesting or different is usually wrong”. The point is, of course, that strange and unusual things in a single poll are more likely the result of sample variation or error than some amazing shift in public opinion, and you should be cautious of them before getting excited (My colleague Joe Twyman likes quoting it without attribution in the hope people will jump to conclusions… not so fast!).

Anyway, today we have a classic case. Two polls that look interesting when compared to recent averages, but which are both probably no more than the result of normal sample error.

Today’s twice weekly Populus poll had figures of CON 32%, LAB 37%, LDEM 10%, UKIP 13%, GRN 4% (tabs). The five point Labour lead is the biggest Populus have shown since November, their 37% share the largest any company have shown since November. Labour resurgence?

Lord Ashcroft’s weekly poll however had figures of CON 34%, LAB 28%, LDEM 8%, UKIP 16%, GRN 8% (tabs.) A six point Conservative lead, by far the best poll for the Tories from any company for several years (the largest Tory leads up to now were the last two MORI polls, which had them three points up). Tory surge?

Of course the actual answer is that there is probably neither a Labour nor a Tory surge, that both of these changes are probably just down to sample error and that people should watch the overall trend across multiple polls, not get overexcited about individual polls. If the figures in one poll look strange or unusual, it’s probably wrong.

In some ways it’s quite nice they come on the same day, as it should stop people getting too excited over an outlier in just one direction. On the other hand, it does tend to produce lots of confused comments about how polls can be accurate when they are showing both a five point Labour lead and a six point Tory lead. Bottom line for those who are confused, part of it is down to pollsters using slightly different methods (in this case, the way Populus weight their polls tends to produce a bigger share of the vote for the main two paries than does Ashcroft). A bigger chunk will be simple margin of error – polls are not precision instruments and no one who understands them would claim they are. They are randomish samples of about 1000 or so people. The quoted margins of error are about plus or minus 3% (though given response rates, weighting effects and that polls are not pure random samples, that’s a bit of a polite fiction). That means if the real position was Labour and Conservative tied on 33%, you would expect to see the Conservatives ranging from 30% to 36% and Labour from 30% to 36%, and while the results would tend to be clustered around the middle of that range, random variation could reasonably vary between a 6 point Tory lead and a 6 point Labour lead. Taken alone and in isolation, it does mean an individual voting intention poll isn’t that useful… which is why you shouldn’t look at them alone and in isolation – watch the trend.

We’re clearly heading towards the Christmas polling break – we’ve still got the usual Populus poll this morning and YouGov poll tonight, but the weekly Lord Ashcroft poll has shut up shop for the year.

All the regular polls tend to stop over Christmas – ostensibly because it’s difficult to get a reliable sample over holiday periods when people have better things to do than answer polls, but I expect there’s a touch of us pollsters needing to have a holiday sometimes too. Last year Populus’s last poll was on the 22nd, so we should have a couple more from them and YouGov normally stop just before Christmas so there are few more from that front too. We also still have the monthly ICM and Ipsos MORI polls to come. ComRes’s monthly telephone poll has been right at the end of each month lately, so we might see that brought forward, or saved until after Christmas. Scratch that last bit – it’s being brought forward to before Christmas, out later tonight.

Anyway, our one poll so far this Monday is Populus’s, with topline figures of CON 34%, LAB 36%, LDEM 10%, UKIP 12%, GRN 5%. Tabs are here.

UPDATE: The daily YouGov/Sun poll today has toplines of CON 32%, LAB 34%, LDEM 6%, UKIP 14%, GRN 8%. YouGov have had the Greens sneaking ahead of the Lib Dems quite a few times lately, but until today it’s only been by a single point.

Meanwhile the monthly ComRes/Indy telephone poll has topline figures of CON 29%(+1), LAB 32%(+1), LDEM 12%(+3), UKIP 16%(-2), GRN 5%(-2). A much better score for the Lib Dems there, the highest that ComRes have shown for over a year.