YouGov’s controversial election model predicts that the Conservatives will fall short of an overall majority in the general election on Thursday.
Its latest projection found that the Tories would get 304 seats, well below the 326 needed to form a majority government.
But most voters and pollsters believe that Prime Minister Theresa May will still secure a majority despite race tightening in recent weeks.
A new Survation poll shows that Labour has slashed the Conservatives lead from 17 points to just one point over the course of the past month.
The poll, for Good Morning Britain, put the Conservatives on 41.5 per cent, just ahead of Labour on 40.4 per cent, with two days to go until the election.
Another Survation poll in Scotland found that the SNP are on track to win 40.2 per cent of the vote, ahead of the Tories on 26.6 per cent and Labour on 25.4 per cent.
Using the Electoral Calculus model, the results form these two polls would give the Conservatives a slim majority of about 331 on election day.
But Survation senior project manager Chris Hopkins warned that these kinds of election models do not take local campaigning into account.
Election 2017 polls latest: Will the Conservatives win a majority?
Mr Hopkins said that pollsters are seeing this year as an “experimental election” because the polls got it so wrong in the 2015 election.
He said that Survation has predicted higher youth turnout than in 2015, adding: “We tend to believe there’s a slightly higher level of youth engagement.”
The huge differences in the latest polls are due to the different ways that pollsters estimate the turnout among young people.
It is thought that younger people are more likely to support Labour, boosting the chances of Jeremy Corbyn’s party in the race.
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Survation has given the Tories the smallest lead in the election race so far. But the latest ICM poll still gives the Tories an 11 point lead.
The new poll from Opinium puts the Tories at 43 per cent, seven points ahead of Labour at 36 per cent.
Betfair spokeswoman Katie Baylis said that the the Tories are still odds-on favourites to win the most seats and a majority in the general election.
But she said: “However we are seeing a significant number of bets on Labour for most seats, which has seen their odds shorten to 9/1 from 14/1 last week and 22/1 two weeks ago.
“When it comes to Overall Majority, the Tories are at 1/4, with no overall majority now backed into 9/2.”