Over the last couple of days the Evening Standard have been reporting the contents of a new YouGov London poll – yesterday here and today here.

YouGov found London voting intentions of CON 35%(nc), LAB 45%(+3), LDEM 8%(nc), UKIP 8%(-2), GRN 4%(nc). Labour are up three since June, but this poll would still suggest Labour doing slightly worse in London than elsewhere (a ten point lead for Labour in London is a 4 point swing since the general election, whereas GB polls are currently showing a 5 1/2 point swing to Labour.)

YouGov also repeated a batch of questions about Boris Johnson returning to Parliament. 37% of Londonders now think it is reasonable for him to seek to return to Parliament in 2015, but 43% think he should not consider doing so until he has completed his term as mayor. If he were to be elected as an MP in 2015 50% think he should stand down as mayor immediately, 34% think it would be okay for him to do both for a year.

Finally today’s poll looked at the possible Labour candidates for London mayor. Tessa Jowell comes top… but only on 12%, narrowly ahead of Diane Abbott on 8%. Amongst London Labour voters Jowell also comes top, but still only on 16%. I think the reality is that questions like this are largely just a recognition contest… and none of the candidates are particularly well known (I haven’t seen anyone even bother asking who should succeed Boris as the Conservative candidate!)

Tonight we have the new monthly ICM poll for the Guardian. Topline figures are CON 32%(-3), LAB 37%(-1), LDEM 12%(nc), UKIP 11%(+2).

More intriguing are the European voting intentions in the same poll – other recent European polls have been showing Labour and UKIP in a battle for first place and the Conservatives off in third place. In contrast ICM are still showing UKIP third, and the Lib Dems now equal with the Greens on a measly 6 percent – CON 25%(nc), LAB 36%(+1), LDEM 6%(-3), UKIP 20%(nc), GREEN 6%(-1).

Why ICM are showing a lower level of European support for UKIP than other pollsters is unclear – there is no obvious methodological reason. ICM weight their European voting intention by likelihood to vote which tends to help UKIP and they include UKIP and the Greens in their European election prompt, so it shouldn’t be a question wording issue. I can only assume it is something to do with the ongoing contrast between the levels of UKIP support recorded in telephone and online polls.

As well as the monthly ICM poll, we also had a YouGov London poll in today’s Evening Standard – tabs here. London voting intentions at a general election stand at CON 34%, LAB 42%, LDEM 9%, UKIP 11%, a swing of three points from Con to Lab, so actually marginally better for the Tories than in GB polls. In European voting intentions the figures are CON 25%, LAB 33%, LDEM 11%, UKIP 24% – so UKIP and the Conservatives fighting for second place behind Labour, a good performance for UKIP in what tends to be a weaker area for them. Finally in Borough elections voting intentions are CON 34%, LAB 40%, LDEM 12%, UKIP 9% – this reflects a swing of 2.5% from Con to Lab since 2010, so would probably be seen as a fairly good performance for the Tories if it was repeated in May. Note the interesting patterns of split votes – there are a lot (18%) of current Conservative voters who would give UKIP their vote in the European elections, but there are also a chunk (12%) of current UKIP voters who would give the Conservatives their vote in the local elections.

Meanwhile the twice-weekly Populus poll had voting intentions of CON 33%, LAB 35%, LDEM 11%, UKIP 13%. Tabs here.

UPDATE: The monthly ComRes telephone poll for the Indy is also out tonight. Topline figures there are CON 30%(-1), LAB 36%(nc), LDEM 9%(nc), UKIP 12%(+1).

Most of the time on UK Polling Report I write about what the polls tell us about public opinion. Only when elections come along do we get to do it the other way around, and see what public opinion tells us about the accuracy of the polls.

As regular readers will know I have deep reservations about naive comparisons of eve-of-election polls and results and pollster “league tables”. They are often used in an extremely simplicistic fashion, with people balancing absurd conclusions upon one pollster being one point closer in a poll with a three point margin of error. One can get a slightly better idea in a well polled election race when consistent trends can be identified (as Rob Ford, Will Jennings et al did at the last election, producing a very different league table) but ultimately all a pollster can really hope for is to be within the margin of error of the result. All else is luck.

Five companies produced polls for the London mayoral election (TNS-BMRB also did one poll, but it was early in the campaign so can’t really be compared). Their final results are below.

YouGov, Opinium and ComRes were all within 3% of all the candidates’ actual support, with YouGov slightly overestimating Brian Paddick’s support, and Opinium and ComRes slightly underestimating Ken’s. On the final round Opinium got the 52-48 split right, with YouGov calling 53-47 and ComRes 54-46. Well done to all three of them.

I’m unsure why Populus – who are normally one of the most accurate and reliable pollsters – ended up so out, showing a 12 point lead in the second round and significantly underestimating Livingstone in the first round. One thing that springs to mind is ethnicity. Since 2008 YouGov have weighted by ethnicity in London polls and it does makes a significant difference to results (Labour support ends up too low without it). There is no mention of ethnicity on Populus’s tables… but then again, neither is there on ComRes’s tabs. Perhaps Populus were just unlucky enough to get a dud sample. They also finished their fieldwork 4 days before the election, so perhaps there was movement towards Ken in those final days (the same applies even more to Survation, whose fieldwork ended 10 days before the election, so there was plenty of time for a swing).

Note that everyone overestimated UKIP’s support… although part of that could be their decision not to put UKIP in their description on the ballot paper (though they still used the UKIP logo, which says UKIP in it.)

Survation and YouGov also produced figures for the London Assembly, figures below.