Play Brightcove video
Reform UK has closed the gap on Plaid Cymru in the race to become the largest party in the Senedd, according to ITV Cymru Wales’ latest poll.
The two parties have consistently polled neck-and-neck but Reform UK has increased its vote share – while Plaid has seen a drop – since our last poll, positioning both parties now tied at 29%.
According to MRP modelling by YouGov for ITV Wales in partnership with Cardiff University, under the new D’Hondt voting system, this round of results means Reform would win 37 seats and Plaid Cymru would win 36.
With both short of a majority it sparks more questions about potential deals with other parties after Wales goes to the polls in just over two weeks time.
Dr Jac Larner, from Cardiff University’s Welsh Governance Centre said: “This poll shows another small drop in support for Plaid Cymru, putting them level with Reform UK at 29%; YouGov’s lowest Plaid estimate since November 2024. All polls come with a margin of error, and we should be cautious about reading too much into a single result.
“But taken alongside the broader polling trend, the signal is clear: the race for the largest party remains between Plaid Cymru and Reform UK, with every other party – including Labour, who were dominant in Welsh politics not two years ago — competing for a distant third place and below.
“What that framing obscures, however, is that finishing first may matter less than it appears. Whichever party leads on seats will face the same coalition arithmetic, and that arithmetic is far more favourable to Plaid than to Reform.
“Plaid has credible partners in Labour and the Greens; a combination of those parties can reach a working majority. Reform has no such options.
“The only party that has indicated any willingness to work with them is the Conservatives, who on these numbers will not come close to bridging the gap to a Senedd majority. In a proportional system, the route to government matters as much as the vote share, and on that measure, the two parties are not as evenly matched as the headline figures suggest.
“A situation where Reform UK are the largest party but find themselves in opposition will nonetheless be a novel one for Welsh voters still adjusting to the realities of proportional government formation.”
The poll keeps Labour on third place at 13% – netting approximately 12 seats – but Welsh leader Eluned Morgan is still predicted to lose her seat.
The Green Party has seen a modest reduction in its share to 10% which would translate to seven seats.
The Welsh Conservatives are up one percentage point to 8% which would bring three seats, although this round of results would not return leader Darren Millar.
The Welsh Liberal Democrats are also up one percentage point to 6% which, in this scenario, would elect just one member – their leader Jane Dodds.
Adrian Masters, ITV Cymru Wales’ Political Editor said: “For the two frontrunners, this poll will have a galvanising effect. Reform UK will use it to urge its supporters to make its gain a reality in terms of votes. While Plaid Cymru’s drop won’t necessarily be unwelcome to that party, shaking up any complacency that may have crept in over the months when its lead was clearer.
“However, the main message remains the same: the vote on May 7th shows every sign of being a change election. Voters here in Wales have clearly decided that they want something different, but they haven’t yet settled on what form that change will take.”
Which parties would represent you according to ITV Wales’ seat projection? Use our interactive map to see a full breakdown of who is projected to win in your constituency.
-
For YouGov’s Senedd Voting Intentions MRP Model there was a total sample size of 2,387 adults. Fieldwork was undertaken between 6th – 15th April 2026. The figures have been weighted and are representative of likely voters in Wales (aged 16+).
From Westminster to Washington DC – our political experts are across all the latest key talking points. Listen to the latest episode below…
