Plaid Cymru has secured a significant victory in the Caerphilly Senedd by-election, with Lindsay Whittle elected as the constituency’s new Member of the Senedd.
The result marks a major upset for Welsh Labour, which had held Caerphilly since devolution in 1999.
The full result was:
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15,961 – Lindsay Whittle, Plaid Cymru
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3,713 – Richard Tunnicliffe, Welsh Labour
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12,113 – Llyr Powell, Reform UK
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690 – Gareth Potter, Conservatives
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709 – Roger Quilliam, UKIP
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516 – Gareth Hughes, Green Party
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497 – Steve Aicheler, Liberal Democrats
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117 – Anthony Cook, Gwlad
Turnout reached 50.43%, making it the first Welsh Parliament by-election to see more than half of eligible voters take part.
Plaid Cymru leader Rhun ap Iorwerth was in Caerphilly earlier in the evening to support Whittle, while Reform UK leader Nigel Farage also campaigned in the constituency on Thursday.
Eight candidates competed in what many described as one of the most closely watched by-elections in the 26 years since devolution.
The by-election was triggered by the passing of Hefin David, who had represented Caerphilly in the Senedd since 2016. Before his death, Labour held 30 of the Senedd’s 60 seats, already depending on the support of at least one opposition member to pass legislation or budgets.
Following this result, Labour will now need backing from two opposition members to win future Senedd votes.
The result comes just six months before the 2026 Senedd election and will be seen as a warning sign for Labour ahead of next May.
It is understood that Labour Senedd members are expected to hold a meeting on Friday morning to discuss the outcome.
The Caerphilly contest could now shape the political landscape as Wales heads towards one of the most competitive Senedd elections in recent memory.
