The YouGov survey published late on Wednesday said if the contest were held now, the Conservatives would snatch 44 seats from the main opposition party to win a 68-seat majority in the House of Commons.
The poll — the biggest so far in this campaign to predict election results seat-by-seat — uses a model that correctly forecast 93 percent of seats in the last election in 2017, according to YouGov.
Britain votes on Dec. 12, with Johnson hoping to secure a majority to be able to push through his plan to leave the EU at the end of January.
The data showed larger swings from Labour to the Conservatives in areas that are more pro-Brexit, especially in England’s northern and central regions.
Labour has promised a new referendum on Brexit, and although leader Jeremy Corbyn says he would be neutral, many of his top team have said they would campaign to stay in the EU.
“As expected, the key thing deciding the extent to which each of these seats is moving against Labour (is) how that seat voted in the European Union referendum” in 2016, said Chris Curtis, YouGov’s political research manager.
The Tories are keen not to seem complacent, however.
Dominic Cummings, a Johnson adviser who masterminded the 2016 Brexit campaign, warned just hours before the YouGov poll was published that the race remained tight.
“As someone who has worked on lots of campaigns, things are much tighter than they seem and there is a very real possibility of a hung parliament,” he wrote in personal blog post addressed to Brexit supporters.
“Without a majority, the nightmare continues. All other MPs will gang together to stop Brexit and give EU citizens the vote,” Cummings added.
Johnson, who took over a minority administration in July, missed his first Brexit deadline of Oct. 31 due to opposition in Parliament.