Plaid Cymru ahead of Reform UK by three points in new Senedd election poll

Martin Shipton

Plaid Cymru has a three point lead over Reform UK in the latest YouGov / Cardiff University poll for next May’s Senedd election, with Labour languishing far behind with the support of just 10% of voters.

Plaid is on 33%, Reform 30%, the Conservatives are also on 10%, the Green Party is on 9%, the Liberal Democrats are on 6% and other parties are on a total of 3%.

A Plaid Cymru spokesperson said: “Something big is truly happening in Wales.

“Coming so soon after our Caerphilly by-election win, this poll shows the momentum is firmly with Plaid Cymru and that next year’s election is shaping up to be a straight choice for Wales’ future.

“After years in power, Labour have given up on Wales. People are tired of broken promises and being taken for granted and yearning for something new: fairness, ambition, and a government that finally puts Wales first.

“At the next election, the people of Wales face two choices of two futures. One is a party rooted in Wales, focused on improving our NHS, public services, and helping families with the cost of living. The other is a billionaire-backed party that would privatise our NHS and take Wales backwards.

“This is a two-horse race, and only Plaid Cymru brings a positive vision, can stop Reform and deliver the new leadership Wales deserves.

“We’re taking nothing for granted, but if people want new leadership and a government that’s on Wales’ side, the choice is clear - get involved and vote for Plaid Cymru on 7 May 2026.”

Wales Green Party leader Anthony Slaughter said: “This poll confirms a pattern we’ve seen all year: Greens will be in the next Senedd. We have outstanding candidates all over Wales ready to serve. Ready to cut people’s bills, fix the housing crisis, and protect the country we love.

“We will make the new government bolder, standing up to vested interests that want things to stay the same. If voters make this poll a reality next May, together we can make the most of this once in a generation chance for fundamental change.”

In a joint post in which they interpret the figures, Dr Jac Larner of Cardiff University and Dr James Griffiths of Manchester University argue that Wales is experiencing a realignment of political support that differs from UK-wide trends.

They state: “While Reform UK's growth reflects broader British patterns, Plaid Cymru's consolidation of progressive votes represents a Wales-specific political development.

“Between November 28 and December 10 we surveyed approximately 2,500 adults in Wales online via YouGov. The headline is largely the same as previous polls: Plaid Cymru and Reform UK polling as Wales' two largest parties, (with slight advantage to Plaid); Labour and the Conservatives
have collapsed to around 10% each; and the Greens up to 9%.

“For the 2026 Senedd election, conducted under the new electoral system, this would see Plaid Cymru and Reform as comfortably the largest parties but both considerably short of a majority.

“To understand what's happening requires recognising that Welsh electoral politics has long been organised around two distinct coalitional blocs, structured primarily by national identity. On one side sits a progressive/Welsh-identifying coalition comprising Labour, Plaid Cymru, and, more recently, the Greens. On the other, a conservative/British-identifying coalition of Conservatives and the various iterations of the UK Independence Party (UKIP, Brexit Party, Reform UK) as well as, previously, the Abolish the Welsh Assembly Party.

“This structure has proven remarkably resilient, surviving even the 2016 EU referendum, which fundamentally restructured British politics around Brexit attitudes.

“The two dimensions - national identity and Brexit - now substantially overlap. British-identifying voters overwhelmingly support pro-Brexit right-of-centre parties; Welsh-identifying voters cluster around anti-Brexit left-of-centre alternatives.

“This alignment creates a robust structure: voters aren't choosing between parties with different Brexit positions within their national identity group. They're choosing between parties that share both their identity orientation and their Brexit/cultural attitudes.

“What makes the current moment distinctive is that we're witnessing consolidation within these blocs rather than mass movement between them.

“Comparing 2021's regional list vote with current polling reveals the pattern starkly. In 2021, Labour dominated the Welsh-identifying progressive bloc, winning the majority of these voters. Plaid Cymru held perhaps a quarter to a third of this coalition. Today, those proportions have nearly inverted: Plaid Cymru has absorbed the bulk of Welsh-identifying progressive support, with Labour retaining only a residual share. But crucially, the total size of the Welsh-identifying progressive bloc hasn't dramatically shifted. These voters haven't abandoned progressive politics or embraced Brexit; they've concluded that Plaid Cymru, not Labour, is the better option for them.

“The mirror image appears on the British-identifying right. In 2021, the Conservatives commanded this bloc as the previous support for UKIP/Brexit Party largely collapsed. Today, Reform UK has absorbed most Conservative support among British-identifying voters. Again, the bloc itself hasn't fundamentally changed size or orientation. It remains pro-Brexit, culturally conservative, and sceptical of devolution. What's changed is which party these voters trust to represent those commitments.

“This pattern of within-bloc consolidation has several important implications. First, it clarifies the coalition/cooperation mathematics that will structure post-2026 governance. Despite their long and sometimes bitter history of electoral competition, Plaid Cymru and Labour remain natural
coalition partners because they draw from the same underlying voting bloc. Their voters share similar identities, Brexit attitudes, and policy preferences, even if those voters currently prefer Plaid to Labour. A Plaid-Labour coalition or collaboration would represent the Welsh-identifying progressive bloc in the Welsh electorate. Added to this mix the Greens and Liberal Democrats, and there are far more natural combinations within this bloc.

“Reform UK and the Conservatives face a different challenge. They too share a voting bloc, but Reform's growth comes almost entirely at Conservative expense and, critically, current evidence suggests they aren't winning enough Labour supporters to substantially grow the overall size of
this bloc. Every Reform vote is effectively subtracted from the Conservatives, weakening the only party with which Reform could plausibly govern.

“Second, within-bloc consolidation suggests different durability than between-bloc realignment. When voters switch parties but remain within their political coalition, they haven't crossed a fundamental psychological threshold. The barrier to switching back is lower, if circumstances change or the new party disappoints. But they also haven't betrayed core identity commitments which makes the switch easier to sustain than ideological conversion.

“The question becomes whether Plaid Cymru can deliver on the expectations of newly consolidated Welsh-identifying progressives, and whether Reform UK can maintain enthusiasm once protest sentiment fades.

“To understand motivations beyond stated party preference, respondents who indicated they would vote for Plaid Cymru or Reform UK were asked to select which statement best described
their choice.

“For Plaid Cymru, the contrast between Labour switchers and Plaid loyalists is stark but common themes emerge. People switching from Labour are heavily motivated by tactical considerations: 30.5% cite ‘They are best placed to stop Reform UK’ compared to 9.5% of Plaid loyalists. This suggests a significant portion of Labour's former vote is consolidating behind Plaid for defensive reasons rather than positive enthusiasm for Plaid itself. Yet Labour switchers aren't purely tactical. Even more Labour switchers (40.3%) cite ‘standing up for Wales’ as their primary
motivation. This is an issue which Welsh Labour have arguably ‘owned’ for the entire devolution period, making the recent collapse in perception on this issue all the more remarkable.

“This combination indicates that Plaid’s consolidation of the Welsh-identifying progressive bloc combines defensive tactics with genuine belief that Plaid better represents Welsh interests.

“Reform UK switching shows a different pattern. Conservative switchers are significantly more likely to select protest motivations: 24.7% choose ‘something new’ compared to 16.3% of Reform loyalists.

Immigration remains the dominant issue for both groups (Conservative switchers 37%, Reform loyalists 44.8%), but the gap suggests loyalists are more ideologically committed while recent switchers include a substantial protest component.

“Leadership matters more for Reform than Plaid. Nigel Farage registers strongly among both Conservative switchers (18.6%) and Reform loyalists (21.7%), underlining the extent that his personal brand is central to the party's appeal.

“Evidence of a political realignment in Wales continues to grow: real world election results (multiple local byelections, and the Caerphilly byelection) and multiple survey datasets from a variety of different providers point to a very different Senedd election in 2026.

“What generates genuinely autonomous Welsh dynamics is voters are increasingly drifting to the Greens or Liberal Democrats. Wales' progressive voters have a credible alternative in Plaid Cymru, but specifically in devolved electoral competition, where the choice is about Welsh governance and Plaid can credibly claim to fight for Welsh interests within Wales.

“This creates a bifurcated realignment with different mechanisms on each side. Reform's consolidation of the British-identifying right reflects British politics playing out in Wales. Plaid's consolidation of the Welsh-identified left reflects Welsh politics asserting autonomy within the devolved electoral context.

“For the first time in a century, Welsh Labour faces the prospect of opposition or junior coalition partnership. That prospect, more than any survey, signals how profound this realignment truly is. The bloc structure that has organised Welsh politics for decades persists, but the hierarchy within those blocs has been overturned.”