Votes are being counted in the crucial Makerfield by-election, where turnout was just under 59%
Results are expected in the early hours of Friday morning - you can follow live coverage on this page
The by-election was triggered by the resignation of Labour MP Josh Simons. Labour's Andy Burnham is trying to return to Westminster - if he wins, he's expected to challenge Keir Starmer for the Labour leadership
His nearest challenger in Makerfield is expected to be Reform's Robert Kenyon
I would say without hesitation this is the most important by-election in my lifetime, writes our political editor Chris Mason
Meanwhile, the Conservatives comfortably win the Aberdeen South by-election, while the SNP holds Arbroath and Broughty Ferry
In growing signs of Labour's confidence in Makerfield, Laura Kuenssberg has read out a message on air coming via Newsnight's Nick Watt.
According to the "unofficial estimate", Labour sources are looking at a 54% vote for Andy Burnham.
Harry Farley
Political correspondent at the Makerfield count
Louise Haigh is the heart of the Andy Burnham campaign. She is close to him and has been integral to the field operation in the towns that make up this constituency over the last few weeks.
So if she is willing to say publicly on TV that she is "quietly confident" at this stage in the night, that tells us Labour think they’ve won.
If they had any doubts Haigh would not be saying that.
It’s not confirmed of course. The votes are still being counted in front of me in the hall. But as things stand here in Wigan, Labour is looking and sounding a lot happier than Reform UK.
Kirsten Campbell
BBC Scotland political correspondent
Douglas Lumsden’s election to Westminster as the MP for Aberdeen South will mean he’ll have to give up the Holyrood seat he won just six weeks ago.
New dual mandate rules prevent him sitting in the House of Commons and the Scottish Parliament at the same time. He must resign as an MSP within 49 days. But another by-election won’t be required.
As a list MSP, his seat will be taken up by the next person on the Conservatives' North East Scotland list, who would be Fraserburgh councillor James Adams - spotted in the front row enthusiastically applauding the Tory victory.
Image source, PA MediaDouglas Lumsden and team celebrate his victory
Image source, PA MediaSNP candidate Lara Bird (second left) is announced as the winner of the Arbroath and Broughty Ferry by-election
The SNP's new MP for Arbroath and Broughty Ferry, Lara Bird, tells her constituents she is ready to get to work.
She says that the by-election was "about the future we want for Scotland".
Bird adds that once again it has made clear that Scotland's future "lies with independence".
She says that "with every day that passes I become more certain that we will win our nation's independence".
Image source, PA MediaThe Conservatives' Douglas Lumsden - the winner of the Aberdeen South by-election - has described the the vote as a referendum on the oil and gas industry.
He says during his victory speech the Conservatives have "sent Labour the message that destruction of the North Sea oil and gas industry must stop now".
"I promise I will be a strong voice for the city, standing up for you and your livelihood against shortsighted policies," he says, thanking his friends, supporters and volunteers.
The SNP's Lara Bird has won the Arbroath and Broughty Ferry by-election.
We'll bring you more on the vote share shortly.
The returning officer is announcing the result for the Arbroath and Broughty Ferry by-election.
You can watch or listen at the top of the page by pressing the "watch & listen" tab.
Douglas Lumsden wins Aberdeen South with a majority of more than 6,000 votes.
The SNP's Stephen Flynn was the MP before winning a seat in the Scottish Parliament this year.
Conservative Party candidate Douglas Lumsden wins the seat for Aberdeen South.
We'll bring you more details on the vote share shortly.
Watch live in our stream at the top of the page.
Louise Cowie
BBC Scotland reporter at the count in Arbroath
They’re about to start adjudicating here, meaning a result shouldn't be too far away.
Senior Labour MP Louise Haigh says that she is "quietly confident" that Labour has won the Makerfield by-election.
Speaking from the count she tells the BBC's Laura Kuenssberg that she does not want to pre-empt the result but she is "optimistic and confident about the result here".
Haigh says she expects the result will be clear in around an hour.
Image source, PA MediaThe SNP's Stephen Flynn has said that it is "a tough night in Aberdeen that some will need to reflect on, quite heavily".
In a post on X he sends his commiserations to his party's candidate Richard Thomson and congratulates Douglas Lumsden, the Conservative candidate.
"We lost Aberdeen South to the Tories in 2017, and we won it back two years later," he says.
"I’ve no doubt that we can do so again. If we get things right."
Flynn was the MP for Aberdeen South before winning a seat in the Scottish Parliament this year.
Harry Farley
Political correspondent at the Makerfield count
Labour sources believe the high turnout in the Makerfield by-election is good for them.
They say it is roughly what they were expecting, meaning they believe they roughly know how many votes they expect to get.
One source close to Andy Burnham was cautiously optimistic at the start of the night. I’ve just spoken to them again and they say are even more confident now.
Remember it’s still early days in the counting process and none of this is confirmed. But certainly people in Labour circles here seem chipper.
Image source, Reuters
Image source, EPA/ShutterstockRestore Britain's leader Rupert Lowe says his party is "bringing people back to vote who haven't voted for a long time".
Lowe, who was elected as a Reform MP in 2024 before launching Restore, says he is "encouraged" by the support his party has.
Speaking from the count in Wigan, he tells the BBC's Laura Kuenssberg he's confident they'll get "much higher" than a suggestion of 2%.
"I think there's an enthusiasm for what we're doing," the Great Yarmouth MP says, adding that the high turnout of 58.75% "should be good" for the party.
Responding to Lowe, Reform's Danny Kruger says he gets the impression Restore's appeal is "largely online" though adds "it may be they do better than expected".
But the PA news agency is reporting that Restore Britain has not got as big a share of the vote as some had anticipated, according to a "Labour source".
James Cook
Scotland editor at the Aberdeen South count
Senior SNP source — “we have lost” Aberdeen South.
The SNP have accepted defeat in the Aberdeen South by-election, the PA news agency reports, with a senior source saying it is the "Tories’ night", but pledging to "win it back in 2029".
Our reporter at the count, Andrew Kerr, earlier said the Conservatives were "extremely positive".
Baroness Smith of Labour tells the BBC she's encouraged by the turnout following the official confirmation of 58.75% eligible voters casting their ballot.
"If we've managed to get that many Labour voters to go out and it's made the difference, that could be good news for us," she says.
But Reform's Danny Kruger refers to earlier remarks by Sir John Curtice, who says high turnouts occur in by-elections when there is an insurgent party, "and that's what's happening now".
"Whatever does happen though it seems obvious we've done extremely well," he says.
Image source, ReutersVoted being counted in Wigan for the Makerfield by-election
Andrew Kerr
BBC Scotland political correspondent at the Aberdeen South count
Shadow Scottish Secretary Andrew Bowie on BBC
The shadow Scottish Secretary Andrew Bowie was live on our TV programme when the Conservative Party chairman Kevin Hollinrake received a message saying his party had won the Aberdeen South seat.
Bowie hadn't heard anything as definitive - and quickly pulled out his earpiece at the end of the interview just to check what colleagues were saying.
The Conservatives are extremely positive and are thinking it certainly looks like they've won - smiles all round for them.
Meanwhile, the SNP are looking very glum in the corner of the count hall.
