But Mr Corbyn could still enter 10 Downing Street as prime minister next month, the polling guru said.
Speaking at Westminster, the Strathclyde University election expert said that the most likely outcomes based on current polling is either a fairly sizeable Tory majority delivering Brexit on Boris Johnson’s terms or a hung parliament resulting in a minority Labour administration propped up by other parties delivering a second referendum.
And the deciding factor in determining between these outcomes may be the performance of Mr Johnson in what is effectively an “unpopularity contest” between two leaders who each provoke historically high levels of dissatisfaction among voters.
Comparing the Conservative leader to a Ming vase, Prof Curtice said: “Boris Johnson is potentially a really valuable asset. You just have to make sure he doesn’t end up on the floor.”
He pointed to Mr Johnson’s fumbling response to floods in Yorkshire and the midlands as an example of the kind of unpredictable event that could yet upend the current 10-point Conservative lead in the polls in the remaining four weeks of campaigning.
Prof Curtice stressed he was not making a forecast of the election result.
But he said: “With a 10-point lead, however you look at it, if that were to transpire in the ballot box, it must be highly likely that the Conservatives will get an overall majority of a size sufficient to enable them to get the withdrawal treaty through.
“Below 6-7 points, the odds swing in favour of a hung parliament. Just because the Tories are ahead in the polls, it doesn’t mean Boris is going to get a majority.”
And he added: “The chances of the Labour Party winning a majority are frankly as close to zero as one can safely say it to be, given that they look to be incapable of regaining anything in Scotland.”
Prof Curtice told reporters the 2019 election was shaping up as a “binary” contest.
With the Democratic Unionist Party implacably opposed to Mr Johnson’s Brexit deal, and the Liberal Democrats and Scottish National Party keen to secure a second EU referendum, another minority Conservative administration propped up by a smaller party seemed highly unlikely, he said.
“Either Boris gets a majority and we are leaving the EU on the terms he has negotiated and will negotiate, or we get a hung parliament in which we have to anticipate a minority Labour administration will be put in to apply for an extension and we will have a referendum.”
There is only a “narrow range of results” which would produce the kind of drama and uncertainty seen in the 2017 parliament, he said.
But he said that the binary choice reflected the balance of opinion seen in polls, with parties prepared to hold a second referendum taking about 52 per cent of support in total and those in favour of Brexit around 48 per cent, compared to the current 53-47 split in favour of Remain in polling on EU membership.
“The reason why the Conservatives are at the moment in pole position in the election is not to do with the popularity of Leave itself, but the fact that the Remain vote is more split,” he said, pointing to research suggesting about three-fifths of Brexiteers plan to vote Tory and only two-fifths of Remainers plan to back Labour.
“The way in which the electoral system treats division gives Conservatives an advantage,” said Prof Curtice. “That’s why the Conservatives want to fight an election and not an EU referendum.”
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