Labour, who have held the Caerphilly seat since it was first created back in 1999, trailed behind Plaid Cymru and Reform UK in third place with a humiliating 11%
Labour has suffered a historic defeat in its Welsh heartlands as it was pushed into third place in the Caerphilly Senedd by-election.
Polling experts said the results showed the party was in “severe trouble” ahead of major elections in May 2026 for the Welsh Parliament.
Plaid Cymru emerged victorious in Caerphilly with a majority of 3,848 votes, and a swing of almost 27% from Labour, on a turnout of more than 50%. Results in the early hours of the morning showed Plaid with 47% of the vote share – compared to 36% for Nigel Farage’s Reform UK.
Labour, who have held the Caerphilly seat since it was first created back in 1999, trailed behind in third place with a humiliating 11%. Conservative candidate Gareth Potter received just 690 votes, with the Greens and Liberal Democrats getting 516 and 497 respectively. But Reform, which also pledged to “throw everything” at its campaign, will also be bitterly disappointed the party failed to swipe the Welsh seat.
In a statement after the Labour defeat, First Minister Eluned Morgan said: “This was a by-election in the toughest of circumstances, and in the midst of difficult headwinds nationally. I want to thank our candidate, Richard Tunnicliffe – a good man who stood because of his desire to serve his community. I congratulate Lindsey Whittle on his victory tonight.
“He returns to the Senedd, continuing his many decades of elected service to people in Caerphilly. Welsh Labour has heard the frustration on doorsteps in Caerphilly that the need to feel change in people’s lives has not been quick enough.We take our share of the responsibility for this result. We are listening, we are learning the lessons, and we will be come back stronger.”
Nick Thomas-Symonds, the Welsh Labour MP and Minister for Europe, admitted Labour has a “very tough fight” on its hands in the Senedd elections next May after its defeat to Plaid. “I certainly accept, and the First Minister – Eluned Morgan – has accepted, that we have a very tough fight on our hands for next May,” he told Times Radio.
He said Labour’s loss was “disappointing” and pointed to a “fractured political landscape” in the UK. “We will listen to the thousands of conversations that we had in Caerphilly about speeding up the pace of change.”
Polling expert Sir John Curtice told BBC Radio 4’s Today programme: “It does suggest that Plaid are now well placed to provide Wales with its next First Minister.” Sir John said Reform will be “disappointed” with the result, but also said it is “pretty consistent” with how Mr Farage’s party has been polling nationally.
“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,” he added.
Rhun ap Iorwerth, leader of Plaid Cymru, said: “Tonight, the people of Caerphilly have spoken loud and clear. They’ve chosen hope over division, and progress over the tired status quo, and backed Plaid Cymru’s positive, pro-Wales vision.
“Lindsay Whittle is a tireless local champion who knows every community in this constituency inside out and will deliver real change for the people of Caerphilly.”
He continued: “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. The message from Caerphilly is clear: Wales is ready for new leadership, and Plaid Cymru is leading the way.”