Editor: this article was written a week prior to its publication, and so some of the information presented may be out of date.
With the decision of the UK parliament to hold a general election on Thursday December 12th, many will be trying to understand what is going on and what might happen. The tool we usually use to track the effectiveness of political campaigns is the dreaded opinion poll. Why are opinion polls so derided? The simple reason is that many pollsters have failed to accurately predict recent political events. This trend is not solely limited to the United Kingdom, but in recent years in this country it has been highlighted by the multiplicity of votes that the British public has participated in. In 2015, a significant majority of polls placed the Conservatives and Labour virtually neck and neck, with some variations either way. The Conservatives won the election by 6.6%, a figure outside the margin of error for most polls. This happened again in 2016, for the EU referendum, and then again in 2017, where many pollsters drastically underestimated Labour Party support. The margin of error is the result of a statistical calculation based on the sample size. Most polls give a confidence interval of 95%, which is usually interpreted as meaning that the pollster is 95% confident that their margin of error contains the true voting intentions of the public (this definition isn’t quite right, but it’s good enough without getting too deep into the stats behind it). So why is it so difficult to accurately measure public opinion? One reason is almost totally beyond the pollsters control, the fact that those taking part lie. For example, there is some evidence to suggest that polls conducted by telephone are less accurate than those online, because the conditions online more properly represent those in the voting booth, in that you don’t have to actually tell someone how are voting, as you do over the phone. This can have an impact on what people are prepared to say as their voting choice. In addition to this, the way questions are asked in polls can have an effect. For example, many pollsters do not list parties such as the Greens and the Brexit Party on their initial list of “prompts”. What this means is that in order to vote for one of these parties in these polls, you have to select the “other” option, whereupon you will be given the option to select such parties.
Having spent all of this time bashing opinion polling, in effect, it does still remain the only method we have for measuring what is going on during the course of a campaign. So, at the start of campaigning, the latest opinion polls available indicate that the Conservative hold around 36%, with Labour on 25%, the Liberal Democrats on 18 and the Brexit Party on 11%. So the Conservatives lead by 11%. This represents a “swing” (that is to say, half the total change in lead compared to the previous election) of 4.25% to the Conservatives from Labour. Such a result would, if it was recreated in every constituency across the UK, see the Conservatives gain 37 seats from Labour, which would, assuming they won all the seats they won last time, give them 354 seats, or in parliamentary terms, a majority of around 68, depending on various other factors (one of which is the amount of seats Sinn Fein win in Northern Ireland). So, job done, then? Oh, if only it were so simple. The problem is that an overall swing is never represented in each individual constituency. For example, gaining support in areas where you are already strong is totally useless under the First Past the Post electoral system. What really matters is the so called marginal seats, those where the last election was a close run affair between two or more parties. That’s why Jeremy Corbyn kicked off his campaign in Battersea, a seat Labour won from the Conservatives by 4.39% in 2017, rather than a hotbed of Labour support such as Liverpool Wavertree, where Labour won almost four-fifths of the vote last time out. It also makes very little to sense to campaign hard in seats that you lost last time out by huge margin, because there is very little chance of winning it, which means it doesn’t really matter in electoral terms. What happens in the marginals is how the election will be decided, not on the basis of the overall swing achieved by a party. The picture is made more complicated by the fact that different regions will have their own stories being played out. Scotland, for example, has shown a noticeably different trend in comparison to the rest of the UK. The SNP appear to have regained much of the ground that they lost in the 2017 election, with the latest polls showing them up six points from 2017, with the Conservatives down by around seven, Labour down by ten and the Liberal Democrats up by six. If replicated across Scotland, which, as we’ve discussed, it certainly won’t be, the SNP would gain back all of the six seats they lost to Labour in 2017, as well as ten of the twelve they lost to the Conservatives.
Looming over all is the question of Brexit. There is a statistically significant correlation between the % of people in a constituency who voted to leave, and the number who voted Conservative in 2017 (no such correlation exists in reverse for Labour, interestingly, but there is one for the Liberal Democrats, although the link is less strong). In close seats, this could make all the difference. Stoke-on-Trent South, for instance, was gained by the Conservatives from Labour last time out, largely a result of the strength of the Leave vote, which was one of the country’s highest, at 70%. Labour gained the traditionally Conservative heartland of Canterbury, a constituency which was 55% for remain in the referendum. However, quantifying this has become even more challenging this election because of the introduction of the Brexit Party. Obviously, they’ll be expected to perform better in areas where the Leave vote was high, but where will those voters be coming from? Will the most significant gains they make be from Labour, the Conservatives or new voters entirely. The best evidence we have to go on is the 2015 election, where UKIP gained 12.9% of the vote, though they only registered a solitary seat (coincidentally, this is around the same number that the Brexit Party are currently polling). Then, UKIP pulled support from both traditionally Labour and Conservative areas, but Nigel Farage was seen as having a far greater effect among older Tories, mostly due to his party being considered right-wing. The Brexit Party has attempted to be more neutral thus far on political issues other than Brexit, but it is still shown as pulling more support from the Conservatives than Labour, by a margin of two to one, perhaps a legacy of Farage’s UKIP days. This has had significant ramification, politically. The Brexit Party could really hurt the Conservative’s chances of winning in several key marginals, such as Dagenham and Rainham, as well as Rother Valley, both constituencies where UKIP came second in 2015, with over a quarter of the vote. If these constituencies’ ex-Kippers vote Brexit Party in similar numbers, the Conservatives are very unlikely to regain them, making their path to a majority far harder. Boris Johnson’s decision to reject Farage’s offer to work with the Conservatives if he rejects the deal he negotiated means he has to try to secure these votes by other means. The question is, can he convince enough hardline Brexiteers to support him and his deal? Thus far, Brexit Party support remains at around 10%, enough to deny the Conservatives at least 20 potential seats, which may prove vital.
From the remain side, the Liberal Democrats can expect to see a much better result than at the last two elections. Their main problem is that their previous level of support is too low for it to a general election win to be a possibility. To illustrate this point, in 515 of the 650 UK constituencies the Liberal Democrats polled below 10% in 2017. Their candidate lost their deposit in 376. Some individual constituency polling, most notably the London constituency of Finchley and Golders Green, has indicated that even such wide margins could be overcome in the election, although this is one of the most heavily remain areas in the country, and it is doubtful that this could be replicated in enough constituencies to make the Lib Dems competitive in terms of national seats. Pockets of individual support, especially in remain-voting areas, will be enough to give them at most 50 MPs, which would represent a return to pre-coalition days.
In Wales, Plaid Cymru are predicted to gain a moderate increase, which will be helped by the pact they now have with the Liberal Democrats, meaning each party will stand aside where the other has a better chance of winning.
The Greens, also part of that pact, are predicted to gain slightly on their disappointing showing in 2017, up to around 5%. This is unlikely to give them anything more than their solitary MP in Brighton Pavilion, Caroline Lucas.
That concludes this summary of the state of play right now in general election.