Gorton & Denton Parliamentary by-election: what three constituency polls tell us
Welcome to the 201st edition of The Week in Polls (TWIP), a newsletter that has been going for longer than Ted Heath was Prime Minister, and with fewer power cuts. This week, I take a look at the opinion polling released for the Gorton and Denton Parliamentary by-election.
This is followed by a summary of the latest national voting intentions polls, seat projections from MRPs, and the most recent party leader ratings.
Subscribers who pay for the full edition can also read ten insights from the latest polling and analysis, including:
How being big on X/Twitter can still leave you obscure with the public;
New data on which social media networks people use; and
More on how Starmer’s polling compares with that for Rayner and Streeting.
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One other preliminary: the first edition of my new podcast, Political Fictions, is out:
In the first episode of Political Fictions, Cory and Mark talk about the 2011 film The Iron Lady. They discuss how the film presents the human side of politicians, what it says about Margaret Thatcher and her legacy, and ponder the appearance of some mysterious milk.
This is also an excuse to share this YouTube video again, featuring Margaret Thatcher as a pop music pundit:
And with that, on with the show.
The three Gorton & Denton by-election polls
Find Out Now
First out of the traps was a poll from Find Out Now, which I covered in TWIP #197:
We have had the first by-election poll for Gorton and Denton. But it had a sample of just 143, and once ‘don’t knows’ are excluded, that falls to 51 people - which causes me to come up with a new rule of thumb: beware of polls where the sample is smaller than the number of Liberal Democrat MPs …
Some of the reactions from other pollsters have been rounded up by Political Betting. Oddly perhaps for a poll that was helpful for Labour (if you think the figures can be relied on), it was made public (by the client, not the pollster) via the Daily Telegraph. Michael Crick has more on the poll here and Find Out Now’s response to the controversy is here. The data tables for the poll - which in fairness it should be pointed out appeared promptly - are here.
It is also worth emphasising that this is the only poll out so far. The figures in Labour’s online adverts with “fieldwork date” and “fieldwork source” are not from a poll; rather they are from an election model. The model is a respectable one, but it isn’t a poll.
You can follow the link to the data tables to see the exact numbers if you really want to.
Omnisis
We also have a by-election poll with a more typical sample size (452), this one from Omnisis and carried out by a mix of phone and online. Excluding undecideds (who are 27% of the original sample) and those who say they would not vote (13%), and after weighting, this comes out as a sample of 265 with:
Greens: 33%
Reform: 29%
Labour: 26%
The data tables for the Omnisis poll are here.
That sample size is getting small after those different stages of the poll. But it is difficult to do a constituency poll, and even more so to do one quickly. Moreover, the greater risk is - I think - not that the sample is too small but that the difficulties of polling either the more mobile younger part of the constituency or the more heavily Muslim part of the constituency has resulted in a skewed sample. Plus as ever it is just the one poll.
Still, it is a reputable poll, and certainly more robust than media coverage of the vibes from rival parties. Omnisis, who have also operated under the brand name We Think, is a Manchester-based member of the British Polling Council and for a while published national voting intention polls. I am not aware of them having done any published by-election polls before, but they do have extensive experience of market research more generally.
Moreover, the discussions I’ve seen from pollsters from other (rival) firms about this poll have been focused on its results rather than picking apart its methodology or accuracy.
The sensible conclusion they all draw is that the poll is a decent piece of evidence which is worth paying attention to, although, given the scope for errors and bad luck with sampling, the figures are too close for us to be able to say with much certainty that those three parties are really in that order.
The Manchester Evening News report on the poll points to Labour figures having a different view:
Labour sources called the poll ‘a load of rubbish’, claiming it had a small sample size and ‘unreliable methodology’. Deputy party leader Lucy Powell MP also refuted the results of the poll, saying on X that it was ‘very clear’ that the race was ‘between Labour and Reform’.
On X/Twitter, Lucy Powell added the claim that the poll “over-indexes Green/Lab wards”.
A further Manchester Evening News piece quotes Labour as saying:
Phone surveys are notoriously poor quality.
The idea that phone polling is “notoriously poor quality” is, well, not a view I’ve known any serious political pollster - including those with Labour leanings - to espouse. And anyway, the poll was a mix of phone and online. (It is also a claim that makes me feel old, remembering how recently it seems that phone polls were held up as a gold standard compared with online polling.)
Ironically, the two phone polls carried out in the final stages of the 2024 general election ended up overestimating the Labour vote. They were hardly alone in doing this, of course, but that is not a helpful sign for making the argument that phone polls are rubbish and underestimate the Labour vote.
But on the over-indexing claim - i.e. that the poll’s sample was skewed towards the more Green-friendly parts of the seat - polling pundit Ben Walker (of Britain Elects and also a Labour councillor but also someone with a solid polling data reputation) wrote of:
A not insignificant overrepresentation of Green friendly wards in the sample of likely voters. Not as bad as Ashcroft’s poll of Runcorn (which oversampled Reform friendly areas and put them 5 ahead), but likely to make a difference of 1-2 percentage points.
Also to note a more large undersampling in Denton. Reform’s capacity to turn out new voters as seen elsewhere means they might be being underplayed here. And whoever is second in Denton may also end up being undersampled.
To me, that is an argument which, at best for Labour, points to more caveats on the closeness of the numbers rather than an argument that points to a major flaw in the poll that significantly skews the picture.
Labour also had a different go at discrediting the Omnisis poll, pointing at who paid for it, but Sam Freedman has it right on this:
However (as YouGov’s Anthony Wells went on to point out in that thread), where bias can come in is over whether or not a poll is released. It may be that there’s another poll commissioned by a Green-friendly source which puts Labour ahead but therefore has been kept private. We just don’t know.
Third poll coming on Monday
To quote from Forward Democracy’s press release which went out yesterday (Saturday):
A similar-sized [to the Omnisis poll] and well-conducted poll commissioned by us (Forward Democracy), which will be published soon by the Byline Times, is consistent with the Omnisis Poll, in relation to there being a tight three-way contest with the Greens slightly ahead of Labour, and a marked increased willingness of Labour supporters to vote tactically for the Green candidate to beat Reform, compared to the willingness of Green supporters to vote Labour to beat Reform.
More from Forward Democracy, also known as StopReformUK.Vote, here and look out in the coming days for details of that poll.
UPDATE: More on this poll, carried out by Opinium, in the Byline Times.
Focus groups in Gorton and Denton
A good way to think about focus groups is that you shouldn’t use a focus group to tell you how many people are doing something, but you can use a focus group to tell you why they are doing it. So don’t expect a focus group from Gorton and Denton to tell us, for example, how far Labour’s support has fallen - but it can tell us something about why it has fallen.
The New Statesman write-up of a focus group of seven Muslims from the constituency is, therefore, well worth a read for the stories it tells us about why some Muslims have moved away from supporting Labour. The intensity of the mentions of Gaza do tell us something useful about this contest, for example. But whether the decline in Labour’s support is on a par with Labour winning or Labour losing, the focus group cannot tell us. Likewise the Lord Ashcroft focus groups in the seat which, although on a larger scale than the single New Statesman one, still are not a poll.
What does this all tell us about the state of play in Gorton and Denton?
What can we conclude from all this?
It is close, at the moment. But it is common for there to be large shifts in opinion at the close of a by-election. Even with significant numbers of people, most likely, having already voted by post, there’s plenty of scope for movement yet. So even if the polling is right, the outcome may be rather different. We’ll never know for sure if polling got it right. Even if the polling is right, it may well be that we do not end up with a close result if the anti-Reform vote starts to coalesce in the last few days of the campaign.
The polling gives us a static snapshot. We do not know who, if anyone, is rising or falling. Imagine, say, that we had accurate weekly snapshots and those latest Omnisis figures showed Labour up 6 points on the last week. That would make the picture look rather different.
The evidence we have is limited and comes with caveats. But Labour’s attempts to rubbish the Omnisis poll are unconvincing.
Alas, we don’t have any net approval figures for the by-election candidates from the published polling. But whoever wins, there are likely to be recriminations over candidate choices: Labour’s decision to block Andy Burnham, or Reform’s decision to go with Matt Goodwin - or both - depending on the result.
Finally, the transparency rules for political polling have once again shown their value. Even though those rules could, even should, be improved, they have done their work here by making sure we know enough about polls to sensibly evaluate them.
Elsewhere from me…
If you spot a factual error…
Borrowing an idea from Stuart Ritchie and others, if you spot a factual error in an edition of this newsletter, I will give you a 12-month free subscription to the paid-for version (or an extra 12 months on your existing one). Factual errors qualify rather than grammatical errors or disagreements over interpretation, with my decision being final. Messages about both of those are always very welcome, though.
Voting intentions and leadership ratings
Here are the latest voting intention polls from different pollsters, and welcome to the Good Growth Foundation (GGF), a new pollster and a member of the British Polling Council (BPC).
The table is also online here. It is updated regularly through the week with new polls.
Next, the latest seat projections from MRPs and similar models, also sorted by fieldwork dates. As these are infrequent, note how old some of the ‘latest’ data is.
Finally, a summary of the latest leadership ratings, sorted by pollster name:
The table is also online here with additional details, and is updated regularly through the week as new data comes out.
For the historic figures for both voting intention and leader approval, including Parliamentary by-election polls, see PollBase.
Catch up on the previous two editions
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The tactical voting landscape, and 9 other polling insights you shouldn’t miss
The following 10 findings from the most recent polls and analysis are only for subscribers who pay for the full edition, but you can sign up for a free trial to read them straight away.
YouGov report that, “Significant numbers of Labour, Lib Dem and Green voters are prepared to vote tactically for each other, as well as the Conservatives, to stop Reform UK”. But how does this vary across different political contexts? This is the key graph:
