Labour’s Michael Shanks won the Rutherglen and Hamilton West by-election on Thursday after securing more than twice the votes of his SNP rival, in a crucial test of the party's appeal in Scotland.
Labour leader Keir Starmer welcomed the “seismic result”, saying that voters in the constituency had “sent a clear message” that it is “time for change”, and that people “believe that this changed Labour Party can deliver it”.
Mr Starmer on Friday said Labour “blew the doors off” in the closely-watched by-election.
Speaking at a victory rally in Scotland, the Labour leader said he was changing the Labour Party's image with voters.
“They said that we couldn’t win in the south of England and the north of England, and we did it. They said ‘you’ll never beat the SNP in Scotland’ and Rutherglen, you did it,” he said. “When I left here a week ago with the team, I said ‘you’ve got to win it’. You blew the doors off!”
The seat In the Glasgow suburb became vacant when former SNP MP Margaret Ferrier was removed in a recall petition.
Ms Ferrier was kicked out of the party for breaching Covid regulations by travelling between London and Glasgow after testing positive for the virus.
Speculation about her position, followed by the recall petition and subsequent ballot have led to months of campaigning in the seat.
The election was the first in Scotland to require voters to show photo ID before being allowed to cast their ballot, after a change in legislation that governs Westminster elections.
The seat has swung between Labour and the SNP at every election since 2015.
The win sends a strong message that Labour is on track to replace Prime Minister Rishi Sunak’s Conservatives as the UK’s governing party at the next general election.
The district, in a former a Labour heartland, was a “must-win” and typical of the kind of parliamentary seat the party had to recover if it is going to take power, said John Curtice, politics professor at Strathclyde University in Glasgow.
Scotland is a target for Labour as it seeks to unseat the Conservatives after 13 years in power, during which time the pro-independence SNP has dominated Scottish politics.
Critical to gaining ground is the willingness of Scots who want to break away from the rest of the UK to “lend” their votes to Mr Starmer to help remove the Conservatives from power.
Support for the SNP has fallen in recent months during a police investigation into its finances.
Backing for independence is largely unchanged, with the nation of 5.4 million split down the middle.
The by-election was also the first major ballot since Nicola Sturgeon, one the UK’s most popular politicians, stepped down as leader of the SNP and head of Scotland’s semi-autonomous government in March.
A recent opinion poll suggested the nationalists could lose as many as 23 of the Scottish seats they hold in the UK Parliament in London.
While Labour would add 19 seats to the single one it held at the beginning at the week, the SNP would remain the largest party in Scotland with 25, based on research by consultancy Stonehaven published in The Times newspaper on Monday.
That said, the poll also found that the SNP would remain the largest party in Glasgow, a city Labour has traditionally needed to win if it is to take power nationally.
Other candidates who stood in the by-election included Tory hopeful Thomas Kerr, who gained 1,192 votes, and Scottish National Party candidate Katy Loudon with 8,399 votes. Cameron Eadie for the Greens gained 601 votes and Gloria Adebo, who ran for the Scottish Liberal Democrats, 895 votes.
