The survey, commissioned by ITV Cymru Wales and Cardiff University’s Welsh Governance Centre, projects a dramatic shift in Welsh politics ahead of the 2026 Senedd election. It suggests Plaid Cymru would secure 30% of the vote, with Reform UK close behind on 29%. Labour trails on just 14%, with the Conservatives on 11%, and the Liberal Democrats and Greens both on 6%.
A Senedd without a majority
If repeated at the ballot box, the poll would leave Plaid Cymru with 38 seats and Reform UK with 37 in the expanded 96‑member Senedd. Labour would be reduced to just 11 seats, the Conservatives to six, with three for the Liberal Democrats and one for the Greens.
With no party close to the 49 seats needed for a majority, the findings point to a hung Senedd and complex coalition negotiations after the next election. The most likely outcome remains a Plaid‑led coalition or working partnership with Labour, given their combined numbers and closer policy alignment.
Labour’s historic dominance under threat
Since the creation of the Senedd in 1999, Welsh Labour has been the controlling force in Cardiff Bay, leading every government and consistently emerging as the largest party. The new poll, however, puts Labour on just 14% — its lowest level of support since devolution.
The slump comes despite Labour’s landslide at July’s Westminster general election, where the party returned to power in London. Analysts suggest dissatisfaction with the UK Labour Government’s early decisions, including its handling of issues such as support for Port Talbot steel, may be contributing to the party’s decline in Senedd voting intentions.
Small shifts, big consequences
The YouGov Barn Cymru poll provides vote share in percentages, which can then be modelled into projected seats. But under the Senedd’s new proportional system, even a tiny change in vote share could alter the way seats are divided. That makes the contest between Plaid Cymru and Reform UK — separated by just a single percentage point — especially significant.
Labour decisions fuel discontent in South West Wales
In South West Wales, the poll highlights how Labour’s recent decisions and controversies are shaping voter perceptions.
In Swansea, Labour largely held its ground at the general election, but the party faced criticism for parachuting in London‑based Torsten Bell as its Swansea West candidate. Now a minister in the Department for Work and Pensions, Bell has been closely associated with the UK Government’s proposed disability benefit cuts, a policy that has drawn sharp criticism from disability groups in Wales.
In Llanelli, Labour MS Lee Waters has faced sustained backlash for his role as transport minister, where he introduced the road‑building ban and the 20mph default speed limit. Both policies have proved deeply unpopular and continue to shape local perceptions of Labour in Carmarthenshire.
Reform UK has capitalised on this discontent. The party came within just 1,405 votes of unseating Labour veteran Dame Nia Griffith in Llanelli at the general election, and has since built momentum with two county council by‑election wins in the town. Much of that rise stems from the Stradey Park Hotel migrant housing controversy, where Reform was highly visible in protests against plans to house asylum seekers, including visits by then party leader Richard Tice.
Taken together, these developments suggest Reform is embedding itself in Llanelli and Swansea, reshaping the political map in areas once considered Labour strongholds. Plaid Cymru remains competitive in Carmarthenshire, but the new proportional Senedd system means even small shifts in vote share could have significant consequences for all three parties.
Corbyn’s new party adds further risk for Labour
The poll also comes as former Labour leader Jeremy Corbyn launches a new left‑wing political movement with Coventry South MP Zarah Sultana. Though still unnamed, the party has already attracted support from Welsh figures including former Cynon Valley MP Beth Winter and ex‑PCS union leader Mark Serwotka.
The 2026 Senedd election will be the first held under Wales’ new closed‑list proportional representation system. Unlike systems where votes can transfer between ideologically similar parties, the closed list offers no such safety net. That means a vote for Corbyn’s party could reduce Labour’s seat share without boosting Plaid Cymru or other progressive parties.
Analysts warn that if Corbyn’s party polls even 5–10%, it could cost Labour and Plaid multiple seats — potentially handing Reform UK a clearer path to power.
What happens next
The Barn Cymru poll underlines just how volatile Welsh politics has become. For more than two decades, Labour has been the dominant force in Cardiff Bay, but its support has now slumped to unprecedented lows. Plaid Cymru and Reform UK are locked in a contest that could reshape the Senedd, while the emergence of Jeremy Corbyn’s new party threatens to fragment the progressive vote even further.
With the 2026 election set to be the first fought under Wales’ new proportional system, even small shifts in support could have dramatic consequences for how seats are divided. What once looked like a predictable political landscape is now wide open — and South West Wales is likely to be at the heart of the battle.
Projected Senedd make‑up
Diagram: Projected Senedd make‑up under the new 96‑seat system, based on YouGov Barn Cymru polling. A dotted line shows the number of seats needed for a majority.
