Nigel Farage has sparked controversy after claiming the Green Party winning the Gorton and Denton by-election was a “victory for sectarian voting and cheating”.
Hannah Spencer, a councillor and plumper, won the poll in Manchester with 14,980 votes, with Reform’s Matt Goodwin second on 10,578 votes and Labour's Angeliki Stogia trailing in third on 9,364 votes, dealing a bitter blow to Sir Keir Starmer.
But concerns were raised about people forcing family members to vote in a certain way during the contest.
Election observer group Democracy Volunteers warned it had witnessed "concerningly high levels" of family voting - an illegal practice where two voters use one polling booth and potentially direct each other on voting.
The organisation said its members saw 32 cases of apparent collusion at polling stations – the highest levels in its 10-year history.
Mr Farage posted on X: "This election was a victory for sectarian voting and cheating. Matt Goodwin was a great candidate for us.
“Roll on the elections on May 7. It will be goodbye Starmer and goodbye to the Tory party.”
The Green Party accused Mr Farage of making an attempt to undermine a democratic result in the by-election.
A Greens spokesperson said: “This is an attempt to undermine the democratic result and is straight out of the Trump playbook.
“We've just won a historic by-election by a comfortable margin.
“We've shown the country that Greens can beat Reform, despite their big business donations.”
Democracy Volunteers said in a statement: “Today we have seen concerningly high levels of family voting in Gorton and Denton.
“Based on our assessment of today's observations, we have seen the highest levels of family voting at any election in our 10-year history of observing elections in the UK.
“We rarely issue a report on the night of an election, but the data we have collected today on family voting, when compared to other recent by-elections, is extremely high.
“In the other recent Westminster parliamentary by-election in Runcorn and Helsby we saw family voting in 12% of polling stations, affecting 1% of voters.
“In Gorton and Denton, we observed family voting in 68% of polling stations, affecting 12% of those voters observed.”
The organisation said it attended 22 of the 45 polling stations in the constituency, spending 30 to 45 minutes in each, and witnessed family voting in 15 of the 22 polling stations observed.
The group said they observed a sample of 545 individuals casting their vote and saw 32 cases of family voting in total, including nine cases in one polling station.
Labour Party chairwoman Anna Turley said the report was “extremely worrying and concerning”.
But Manchester City Council hit back that no issues had been reported and said it was “extremely disappointing” that Democracy Volunteers waited until after the close of polls to make the claims.
A spokesman for the Conservative Party, which came a distant fourth and saw the candidate lose their deposit after gaining just 1.9% of the vote, said: “Keir Starmer has killed the Labour Party.
“In losing one of Labour's safest seats, in a constituency that has returned Labour MPs for almost a century, Starmer has shown he no longer commands the support of Labour voters and is now a lame duck leader.”
Polling expert Sir John Curtice said that “nervousness” will be heightened in Labour after the result but cast doubt on the prospect of Sir Keir facing a leadership challenge before the May local elections.
He told BBC Breakfast: “There are two big messages that come out of this. The first, of course, the most immediate, is that the nervousness that already existed inside the Labuor Party about Keir Starmer's ability to turn around his party's electoral fortunes, that nervousness is now going to be heightened.
“Not that there will be any move against the Prime Minister before May 7, but his chances of surviving after May 7 if the results are bad, have, I think, been diminished.”
