Exclusive Survation poll for Camlas, Wales’ largest public affairs company – shows a close contest between Reform (42%) and Plaid (38%) ahead of next week’s vote, signalling a major shift in the Welsh political landscape after 26 years of Labour dominance, as well as over a century of Westminster and Senedd control in Caerphilly.

Summary

A new Survation telephone poll for Camlas ahead of next week’s Caerphilly Senedd by-election shows a close race between Reform UK (42%) and Plaid Cymru (38%), with Labour trailing on 12%. The result highlights a major realignment in voter sentiment in Caerphilly, with large numbers of former Labour and Conservative voters shifting to both Plaid and Reform. The by-election – likely the last held under Wales’s current voting system – provides some confirmation of recent national polling seen in Wales ahead of next year’s Senedd elections.

Headline Voting Intention (likely voters vs 2021 Senedd elections)

Base: All those likely to vote with undecided squeezed and those still undecided and refused removed

If the by-election were held today:

– Llŷr Tomos Powell – Reform UK:   42%    (+40)

– Lindsay Whittle – Plaid Cymru:   38%   (+10)

– Richard Tunnicliffe – Labour: 12% (-34)

– Gareth John Potter – Conservative:   4% (-14)

– Steve Aicheler – Liberal Democrat:   1%  (-1)

– Gareth Hughes – Green Party: 3%  (+3)

(Others +/- 0) 

Key Findings

Reform UK leads overall (42% vs Plaid on 38%), driven by strong support among older voters (49% among 55+).

Reform is attracting just over a quarter (26%) of Labour 2021 voters, 18% of Plaid 2021 voters and a massive 70% of Conservative voters since the last Senedd election in Caerphilly.

Plaid Cymru dominates among younger voters (50% among 18–34s) and performs consistently across wards. 

Plaid is attracting 31% of 2021 Labour voters and 19% of 2021 Conservative voters not enthused at the prospect of Reform.

Labour’s 2021 base in Caerphilly has fragmented since the 2021 Senedd election: only one in three (33%) of its 2021 voters remain, while 31% have switched to Plaid and 26% to Reform.

Labour’s remaining  vote is concentrated among older core supporters (15% among 55+).

Conservative support has collapsed, with around 70% of 2021 Senedd Conservative voters now backing Reform.

Context and Interpretation

– Results would indicate a major reshaping of Welsh politics, with Labour’s long-standing dominance under pressure from both Reform and Plaid

– Reform’s strength among older voters contrasts with Plaid’s youth-led appeal, reflecting emerging generational divides within the Welsh electorate.

– The collapse of the Labour vote is matched by that of the Conservatives, signalling the continued decline of the traditional two national  parties in favour of insurgent electoral forces and local parties.

– If replicated at a national level, these shifts would signal a transformational moment in Welsh electoral politics, with multi-party competition returning to areas long seen as Labour heartlands.

Damian Lyons Lowe, Chief Executive of Survation, who conducted the poll said:

Welsh politics is on the cusp of an unprecedented transformation. The Labour and Conservative parties previously took a combined 63% of Caerphilly’s Senedd vote in 2021 – our polling indicates this may have plummeted to just 16% as both have seen an extreme fragmentation of their vote to both Reform and Plaid.

While Labour’s one hundred year long unbeaten record in Caerphilly’s Senedd and Westminster elections is highly likely to be coming to an end, this type of result being replicated nationally would also see the end of over twenty years of Labour Welsh Government dominance , with Reform or Plaid the likely party of power in 2026.

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GET THE DATA.

Survation conducted an online poll of 501 Caerphilly residents aged 16+. Fieldwork was conducted between 7th – 14th October 2025 on behalf of Camlas. Tables are available here.

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