When Theresa May called for a snap election on April 18th the Conservatives had good reason to feel confident. An ICM poll that day showed the Tories with a lead of 21 points over Labour and in the following days that lead widened to an eye-watering 25 points in one poll.

Conservative confidence was buoyed not just by strong national polls but by a series of polls in Wales and Scotland that showed the party advancing across the British mainland. One poll in Wales showed Theresa May’s party on 40% of the vote there with Labour languishing behind on 30% – an unprecedented position for the Conservatives in Wales. Meanwhile in Scotland, one poll showed Ruth Davidson’s Scottish Conservatives on 33% – just 11 points behind the SNP.

The growing sense that this election had already been won was only added to by the local election results in May. The Conservatives gained 161 councillors in Scotland, 80 in Wales and 319 in England whilst Labour slumped to a 27% share of the vote. All the indications were that the Conservatives were on course for a landslide. With a majority all but certain, focus turned to the question of how large the Conservative majority might be.

Yet polls are fickle beasts and since something has clearly changed since the local elections.

Gone are the Conservative leads of 20% or more as the opinion polls have increasingly shown the Labour vote moving upwards. Since the May 15th not a single poll has shown Labour falling below the 30% they garnered in 2015 and their vote share is increasingly in the high thirties. On Wednesday night Yougov released a poll showing Labour on 39%, just 3 points shy of the Conservatives on 42%.

This change has been picked up in Scotland and Wales as well. In Scotland, an Ipsos-Mori poll suggests that Labour have caught up with the Conservatives with both parties sitting on 25%, with the SNP eighteen points clear on 43%. In Wales the Conservative lead has been reversed with Labour now 10 points ahead on 44%.

That said, the polls do not agree on the extent of Labour’s recovery. On the same day that YouGov suggested Labour were only 3 points behind the Conservatives, Kantar and Panelbase predicted Tory leads of 10% and 15% respectively. Whilst the pollsters all agree that the race has tightened, how are we to know which pollster to trust? Will the Tories lose their majority (as YouGov has suggested) or will they return with a majority of over 100?

This is not the first time that pollsters have sent mixed signals. In the lead up to the 2015 General Election many polls indicated a very close race with several actually indicating a tie just days before the vote. As it happened, David Cameron’s Conservative Party won 36% of the vote and a majority in the House of Commons with Labour slumping to just 30%.

The British polling industry was also unable to unanimously predict the outcome of the EU referendum in June 2016, with some pollsters showing the Remain side 10 points ahead just days ahead of a vote that Leave won 52-48. They also suggested that the margin of victory for the No campaign in Scotland’s Independence Referendum would be much smaller than it was with a number of polls even putting Yes ahead – in the end the No campaign won by 10 points.

The pollsters themselves argue that they have attempted to change their models to make them more accurate. An inquiry into the industry after the 2015 General Election found that they had included too many overly-engaged young people in their samples and most pollsters have now responded by altering the weights given to certain respondents and by altering turnout models.

Yet even with these changes many pollsters are noting a sudden uptick in voters aged 18-25 saying that they’ll definitely vote and definitely vote for Labour. The biggest question facing pollsters right now is whether these respondents will actually do what they say they will. Generally speaking, those that think they won’t are showing the Conservatives further ahead, those that think at least some of them might are showing a tighter race. Come election night one or both models will be shown to be flawed.

In all this, it is worth pointing out that not a single poll has yet shown Labour ahead. And the surge in support for Labour will no doubt help motivate Conservative voters to go out and vote in record numbers. Ultimately these polls themselves could be the very thing that guarantees a Tory win. Yet one thing is for sure – young people will help decide this election simply by turning up.

Also published on Medium.