General Election Polls 2019: The big Conservative poll lead isn’t nearly as big as it looks This is a complicated election, and the Conservative poll lead obscures a fragile national picture

After a few weeks of stagnant polls, the gap between Labour and the Conservatives had begun to very gently close. But in the middle of last week all hell broke loose when the Brexit Party stood down in more than half the seats in the country, and once the dust had settled, and some candidates had unilaterally pulled their nominations, the Brexit Party was standing in 274 seats. That’s fewer than Nigel Farage originally promised, with the Brexit Party not just avoiding the seats the Tories won in 2017, but also a number in the very Remain-voting Scotland.

Pollsters now have to account for exactly how to measure people’s intention to vote for the Brexit Party, as many won’t have a candidate to back in their constituency. Now the candidate selections are final, pollsters will give respondents the names of actual candidates, rather than just parties, and won’t offer the Brexit party to people who won’t be able to vote for them. The new methods should also help account for any incumbency advantage (though that itself is of questionable value).

The problem is what we can extrapolate from those polls, as the national vote share becomes a potentially inexact measure, and there’s a significant likelihood that the Conservatives are piling up votes in broadly safe seats they already hold, and making fewer inroads into the northern seats they want to win than the polls would suggest. This is causing problems for the classic models most people are used to seeing.

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Uniform swing

Typically, one of the safest ways to project an election is based on uniform swing. Though it has always had problems with regional parties, and despite seat-by-seat errors, the overall pattern tends to match up. Now England and Wales is essentially split into two separate regional elections (well, actually there are at least six elections happening), but we’re still seeing one national voting intention to describe it.

Take the SNP as an example of where uniform swing breaks down regionally. In 2017 they got 3 per cent of the vote nationally, but in the 59 Scottish seats they got slightly over 36 per cent. The small overall size of the vote means the national polls are poor predictors, as a 1.7 per cent swing resulted in 21 seats changing hands.

According to the polls, The Brexit Party is currently at somewhere between 4 per cent and 6 per cent nationally, which is also roughly the size of a similar increase in the lead to the Conservatives. Despite the concerns about Labour Leavers going to the Brexit Party, the majority of their voters are still ex-Conservatives.

The lead increase for the Conservatives only really exists in the 317 seats that the Brexit Party aren’t standing in, plus a couple of very marginal seats, and some Scottish seats they barely had a presence in. In the other areas, such as Tory target seats, the likely Brexit party standing is much higher than the polls suggest, and the Conservative lead lower. Overall, the Brexit party is probably doing slightly more than twice as well as the national vote picture indicates.

The recent poll by ICM confirms this specifically, saying that at the moment, “the Brexit Party vote appears to hold up well among those who were shown the party, claiming 10 per cent of the vote among this group”.

Additional complications

Ultimately, the Conservative half of the country is seeing a Conservative generic lead that’s even higher than the polls say – around 15 points. The non-Conservative part is seeing a generic lead that’s much smaller, around 7 points. But that baseline doesn’t mean the Conservatives actually lead in those areas. In fact, it simply suggests a swing from the previous national vote – which was a Conservative lead nationally of 2.5 points. Across the seats the Conservatives won in 2017, the Conservative overall lead in 2017 was over 25 points. In the seats they lost, it was nearly 25 points in favour of Labour (a tautological inevitability).

What that means is we’re seeing a swing to the Conservatives of around 4-6 points in non-Conservative held seats, not of 10-11, where the polls have it. That actually only puts around 35 Conservative target seats in play.

But the Conservatives are also losing seats in Scotland thanks to the resurgence of the SNP, as well as some potential other losses in London and the South West to the Lib Dems, and independents like Dominic Grieve. If the Brexit Party vote holds up (which is a big “if”), the most likely result, even with a double-digit poll lead, is a fairly small Conservative majority.

Then an additional complication is that the Brexit Party vote also isn’t distributed evenly across the country. The somewhat questionable Focaldata MRP polling model, conducted before the campaign, showed that in some Tory target seats, the Brexit Party was getting 20 per cent of the vote, and in other, more Remain seats, it was well under 10 per cent. It’s not that surprising, as Labour has both the most Remain and most Leave seats in the country, but means that the Brexit Party is likely to be doing better, and eating into the Conservative lead more in Tory target seats, preventing them winning as many as they’d expect despite the big poll lead.

Overall, the 8-17 point lead the polls are currently showing is likely to result in a Conservative majority if it held into the election, though even at the higher end there’s a reasonable chance that the majority is less stonking and more modest than that gap would imply. If the polls start to close a few points more, or the polls showing a much lower lead proves to be correct, the results could start to get very complicated.