Labour would “undoubtedly” win a majority if the result of the Chester by-election was replicated at the general election, a leading polling expert has said.
Professor John Curtice said Labour was now in a “stronger position” than at any point over the last 12 years.
The party held Chester on Thursday and increased its majority over the Tories in the seat 6,164 to 10,974. Samantha Dixon was elected the new MP.
Curtice said the result “probably confirmed” the polls showing Labour had a 20 point lead nationally over the Conservatives.
Asked by BBC Radio 4′s Today programme if the result was an election winning one, he said: “Oh yes.
“It wouldn’t produce an enormous Labour majority. But it almost undoubtedly would be enough to produce an overall Labour majority.”
This would put Keir Starmer in No.10 as prime minister at the election, due in 2024.
“With the possible exception of the Middlesborough by-election in 2012, this is the best performance by Labour - the biggest swing from Conservative to Labour in any by-election since David Cameron first walked through the door of No.10,” Curtice said.
He added Labour was now in a “stronger position than they’ve been at any previous point when they’ve been trying to challenge the Conservatives over the last dozen years”.
Lord Robert Hayward, a Conservative peer and another elections analyst, told Sky News there were “no shocks” at by-election, given the Tories were expected to lose.
But added there was “no question” Rishi Sunak and the Conservatives have a “real challenge on their hands”.
The by-election was called after the incumbent Labour MP Christian Matheson resigned after complaints – which he denied – of “serious sexual misconduct”.
It was the first by-election since Boris Johnson was ousted and the market chaos that defined Liz Truss’s short stint in No.10.
A YouGov poll released on Thursday, as voters went to the polls in Chester, showed Labour hold a 25 point lead nationally over the Conservatives.