image source, Getty Images
- the author, Sir John Curtis
- the role, Professor of Politics at the University of Strathclyde
A trio of recent opinion polls predict that Labor is on course to win a landslide majority in the general election.
So are the Conservatives really on the way to an electoral “wipe out”? Or should we doubt the poll results?
First, what old-fashioned polls are telling us – those that typically interview between 1,000-2,000 people to estimate the parties' overall UK-wide vote share.
At least 16 companies have conducted at least one such survey in the seven days since Monday last week.
Labor averaged 41% in these polls – three points lower than where they were at the time of Rishi Singh's election.
But he is still 20 points ahead of the Conservatives, who are now on 21 per cent – three points below where they were at the start of the campaign.
According to these regular polls, the Prime Minister's campaign has had no success in reducing Labour's lead.
The party that has acquired the land is Reform UK.
Since Nigel Farage announced he was taking over as leader and running as a candidate, support for reform has increased by five points compared to the start of the campaign.
The Liberal Democrats have also gained slightly – they are now running on 11% – up one point in the campaign. Meanwhile, the Greens have the 6% they started with.
Of course, regular elections have not always been fair. But two things stand out from these numbers.
Firstly, only 62% of people are saying they are going to vote Conservative or Labour.
This would be a record low since Labor first became a genuine challenger to the Conservatives in 1922.
And secondly, the Tories have never before been so low in the opinion polls – including at least during a general election.
MRP 'Mega Poles'
But what about the polls that predicted a large, indeed in some cases huge, Labor majority?
The three most recent polling companies are from YouGov, Savanta, and More in Common and use a so-called multilevel regression and poststratification (MRP) model.
They usually interview a large number of voters, in some cases as many as 40,000.
Because they interview so many people, they can find out how people with different demographic characteristics—such as gender, age, and educational background—distribute their support among the parties.
Meanwhile, sources such as the census tell us how many people of a demographic group live in each constituency.
By combining these two sources of data, statisticians can estimate how many people are likely to vote for each party in each constituency.
As a result, these MRP polls give us an idea of how fluctuations in party support vary across the country since the last election. Under our electoral system this variation can play a key role in determining how many seats each party will win.
All recent MRP polls suggest the Conservatives could win fewer seats than in any previous election. His all-time low was 156 in 1906.
However, their estimates of the return of Conservative MPs ranged widely – from a low of 53 to a high of 155.
So why are all the estimates so low? And why is there so much difference between them?
All these polls suggest that the Conservatives are losing support in the constituencies they are trying to defend from seats already held by the opposition.
If that happens on July 4, the Conservatives will lose far more seats than they would if their support fell by more or less the same amount everywhere.
However, MRP polls disagree on how much the Conservatives' vote is currently falling in their seats.
For example, More in Common estimates that in constituencies where, in 2019, the Conservatives were 25 points or more ahead of the second-placed Labor candidate, the Tory vote is currently 23 points lower on average.
By contrast, seats where Labor was first and the Conservatives second last saw Tory support fall by 12 points – 11 points.
'Safe Seats'
However, in their poll, which suggested that the Conservatives could win at least 53 seats, Savanta and Electoral Calculus estimate that the difference in the average drop in Conservative support between the two types of seats is 21 points.
Their polls say support for the Conservatives is down by an average of 33 points in their safe seats.
No one can be sure where the truth lies between these two estimates. How best to predict unusually fast fluctuations in Conservative support is a matter of debate in the polling community.
But there is good reason to believe that some such pattern will emerge.
On average, Conservative support is currently down 24 points in regular polls across the UK in 2019. However, the party won less than 24% of the vote in the maximum 100 seats in 2019 – so, if the polls are right, Conservative support will be falling further elsewhere.
Meanwhile, Reform UK's predecessor, the Brexit Party, did not contest Conservative-held seats in 2019. This time the party is standing in most Conservative-held seats. It means his lead now, largely achieved by winning over one in four Tory voters in 2019, is the strongest in such seats – mostly at the expense of the Conservatives.
But how likely is Tory support to fall? No one can believe it. But the fate of many Tory MPs may well depend on what the answer proves to be.
Sir John Curtis is Professor of Politics, University of Strathclyde, and Senior Fellow, National Center for Social Research and 'The UK in a Changing Europe'. He is also the co-host of the Trendy Podcast.