Labour is in “severe trouble” in Wales, polling expert Sir John Curtice has warned, after the party suffered a brutal defeat in a by-election in its heartlands.
Plaid Cymru snatched the traditionally Labour seat of Caerphilly away from Sir Keir Starmer’s party despite a surge in the Reform UK vote overnight on Friday.
The result, which saw Labour come third, marks the first time the party has lost a vote in the former mining town in more than a century.
Labour has run the Welsh parliament since the devolved administration was first established in 1999 and Caerphilly has been one of its strongholds.
But opposition parties hoping to form the next Welsh government have run fierce campaigns in the South Wales constituency, with many seeing this week’s by-election as a bellwether for the Senedd election next May.
Speaking to BBC Radio 4’s Today programme, Sir John said: “Labour’s share of the vote was just 11 per cent. It fell by 35 points. That’s the biggest drop that Labour have ever suffered in a by-election in Wales. Labour are in severe trouble in Wales.”
He added: “It does suggest that Plaid are now well placed to provide Wales with its next first minister.
“Reform will be disappointed at coming second with 36 per cent but I don’t think we should run away with the idea that this, in any way, suggests that Nigel Farage’s bubble is burst.”
Sir John said Reform UK’s result is “pretty consistent” with how Mr Farage’s party has been polling generally.
“It’s just that it isn’t going to be strong enough to win an election if you’re facing a strong alternative, which in this case was Plaid, whereas of course in the county council elections earlier this year that wasn’t the case.”
Lindsay Whittle, a long-standing councillor in the Penyrheol ward and leader of the group on Caerphilly Council, won the seat with 47.38 per cent of the vote – a swing of almost 27 per cent from Labour.
In second place was Reform UK’s Llŷr Powell on 35.9 per cent, while Welsh Labour’s Richard Tunnicliffe came third with just 11 per cent.
The result will also be seen as a disappointment for Reform UK, which was polling in front and had hoped to win its first seat at the ballot box, with Mr Farage pledging to “throw everything” at the campaign.
While the party’s vote share increased significantly after winning just 495 votes four years ago, it is thought that tactical voting to keep Reform out of office took place, dampening the party’s success in the constituency on Friday.
However, the final result put Reform well ahead of Labour and has bolstered hopes that the party could oust Sir Keir’s government at the next election.
The election marks the first time in history that a Senedd by-election has exceeded 50 per cent turnout.
The result will embolden Plaid in its efforts to enter government in Wales next year, and is a bitter blow for Labour, which had held the seat since the Senedd was first established.
Plaid Cymru leader Rhun ap Iorwerth said the result shows the people of Caerphilly have chosen “hope over division, and progress over the tired status quo”.
“This result shows that Plaid is no longer just an alternative. We are now the real choice for Wales, the only party able to stop billionaire-backed Reform and offering a better future that works for everyone,” he said.
Meanwhile, Mr Whittle said: “Tonight’s result shows what’s possible when people come together to back practical solutions and protect what matters most.
“We’ve beaten billionaire-backed Reform and, with the same determination, we can do it again in May 2026. Caerphilly has shown the way – now Wales must follow.”
Mr Whittle received 15,961 votes, up almost 19 per cent from the 2021 result in the constituency and representing a swing from Labour of almost 27 per cent.
Mr Powell got 12,113 votes while Labour's Mr Tunnicliffe trailed on 3,713, down from 13,289 in 2021, when there was a lower turnout.
And as Labour reels from the Caerphilly by-election result, a poll by Techne UK has dropped, revealing that the Green Party surge is hurting Labour.
Techne’s first poll for a month – the first since the Greens elected Zack Polanski as leader – shows the party up three points to 12 per cent while Labour has fallen to 19 per cent, below 20 per cent for the first time in Techne’s polling.
Reform are on 29 per cent, the Tories 18 per cent, and Lib Dems 16 per cent. Meanwhile, less than one in 5 (19 per cent) express any level of confidence in the government.
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