Plaid Cymru wins Caerphilly by-election; Labour third
Caerphilly just sent a message Wales can’t ignore. In a Senedd by-election that asked voters to pick a direction, you picked change. Plaid Cymru won, Reform UK surged into second, and Labour slipped to third. Let’s walk through what happened and why it matters for you.
Here are the core results. Plaid Cymru’s Lindsay Whittle won with 15,961 votes (47%), Reform UK’s Llŷr Powell took 12,113 (36%), and Labour’s Richard Tunnicliffe finished on 3,713 (11%). These are big moves in a seat many assumed was safe for Labour.
Turnout tells its own story. At 50.43%, this was the highest participation ever recorded for a Senedd by-election, suggesting that when the stakes feel real, people do show up.
Why did the vote happen? The seat became vacant after the death of Labour MS Hefin David on 12 August 2025, with polling held on 23 October. BBC reporting also notes this could be the final Senedd by-election before new rules kick in.
Context matters. Labour had dominated Caerphilly for more than a century at Westminster and had never lost the Senedd seat since 1999. That run ended last night; BBC News called it Labour’s first parliamentary defeat in Caerphilly in 100 years.
What helped Plaid? Many of you told canvassers you wanted practical fixes-jobs, the NHS, and a better funding deal for Wales-and a clear way to stop Reform UK locally. Plaid’s pitch spoke to that mood, while the constitutional question of independence stayed in the background during this race.
Reform UK’s surge is real. Growing from a tiny 2021 base to 36% and more than 12,000 votes shows an operation learning fast, even if it fell short on the night. Both ITV News and Reuters underline that jump and the intensity of the campaign behind it.
Labour now faces hard choices. From leading here with almost 46% in 2021 to 11% today is a steep fall; national figures called the result disappointing and promised to listen. The task ahead is a clearer, Wales-first story about delivery in communities like yours.
Quick civic note: this by-election used first-past-the-post, where a split opposition can hand victory to the leading challenger. The 2026 Senedd election will use a new closed-list proportional system, and future vacancies will be filled from lists rather than by-elections-so this may be the last Senedd by-election we cover.
What it means right now. Plaid adds a seat and momentum; Labour continues to run Wales but without a majority and with tougher budget maths; Reform proves it can mobilise thousands. Reuters and the Guardian both set out the wider UK ripple effects of Caerphilly.
Media literacy check: loud rallies and viral clips can make a contest look like a two-horse race all by themselves. Nigel Farage says the next Senedd vote will be just that; your job is to test claims against facts-policies, delivery, and coalitions under proportional rules.
Looking to May 2026, watch three things: which priorities parties fund in health and local services, which alliances they’re willing to discuss under the new voting system, and whether turnout stays above 50%. The date is set for May; we’ll be here to explain every step.