The Scottish National Party was forecast to suffer its worst result in a British general election since 2010 on Thursday, dealing a blow to Scotland's flagging independence movement.
An exit poll released after voting stopped at 10:00 pm (2100 GMT) predicted that the SNP would lose dozens of seats and be overtaken by Labour as Scotland's largest party in the UK parliament.
The poll said the pro-separatist party would win only 10 constituencies in Scotland, down from the 48 it won at the last election in 2019, losing its position as Britain's third-biggest party.
Ex-SNP leader and former Scottish leader Nicola Sturgeon said the prediction was "at the grimmer end of the expectations" for her party, which had been tipped to endure a chastening performance.
"This is seismic for Labour. There's no getting away from that, it's a massive achievement for Keir Starmer," she said of predictions that Labour would defeat the ruling Conservatives in a landslide.
The SNP has dominated in Scotland in the last three UK elections, peaking with the 2015 vote when it won 56 seats out of 59 seats. In 2010, it got only six seats.
But the party has been under pressure from the resurgence of Labour in its former heartlands north of the English border, as it rides a wave of displeasure against the Tories nationwide.
Scotland sent only one Labour MP to the UK parliament in Westminster in 2019 but was expected to return scores of lawmakers, as Starmer's party was tipped to win 410 seats and secure a majority of 170.
The SNP was expected to be overtaken by the Liberal Democrats and Nigel Farage's right-wing upstarts Reform UK, slumping to fifth position in party size at Westminster.
The SNP has been in turmoil for months as voters tire of its 17 years in charge of the devolved Scottish parliament in Edinburgh.
Critics have also accused it of focusing on independence at the expense of key issues such as the cost-of-living crisis, education and health.
Support for the SNP has also slumped amid a finances scandal that saw Sturgeon's husband, Peter Murrell, charged with embezzlement. Murrell is the party's former chief executive.
Sturgeon herself was arrested, but released without charge.
Current SNP leader John Swinney only took charge in May following the resignation of Humza Yousaf after the collapse of the SNP's power-sharing deal with the Scottish Greens in Edinburgh.
Yousaf was in power for just over a year.