Labour support collapses as Plaid Cymru and Reform battle it out for Senedd election — ITV poll

• ITV Cymru Wales' Political Editor Adrian Masters reporting.

Labour support in Wales has slumped to its lowest since the start of devolution, according to an exclusive ITV Cymru Wales opinion poll which suggests Plaid Cymru and Reform UK will battle to be the biggest party at the 2026 Senedd election.

The Barn Cymru poll, conducted by YouGov for ITV Cymru Wales and Cardiff University, has revealed that Labour’s predicted vote share - 18% - would be their worst result since the advent of devolution 26 years ago if replicated at next year's Senedd election.

The poll shows a large increase in Plaid Cymru’s vote share, which climbs to 30%, while the support for Reform has also continued to surge to 25%.

Senedd voting intention:

Plaid Cymru - 30%

Reform UK - 25%

Labour - 18%

Conservatives - 13%

Liberal Democrats - 7%

Green - 5%

Other - 2%

Dr Jac Larner, from Cardiff University's Welsh Governance Centre, said: "This poll represents a substantial shift from previous Welsh polls and as always carries the health warnings of a single poll.

"However, the results support a broader pattern emerging throughout the UK - both Labour and Conservative parties are experiencing substantial erosion of support, though flowing in different directions, resulting in a newl fragmented four-party political landscape in Wales."

How would these poll results translate into Senedd seats?

"Modelling indicates Plaid Cymru would emerge as the largest party with approximately 35 seats, followed closely by Reform UK with 30 seats," Dr Larner said.

"If these polling figures were replicated in an actual election, Labour would secure 19 seats, while the Conservatives would hold nine seats and the Liberal Democrats three seats. However, it's important to note that 10 of these projected seats fall within a very narrow margin of error (less than 2%), meaning even minor shifts in vote intention could produce a substantially different Senedd composition."

Tensions between Wales' First Minister Eluned Morgan and Welsh Labour MPs have been mounting in recent months, with the FM telling the party's Westminster representatives they need to do more to stand up for Wales.

Meanwhile, the Labour-run UK Government's recent cuts to benefits and winter fuel allowance have been widely unpopular across the country and have been difficult politically for Welsh Labour to defend against attacks from opposition parties.

In a speech marking one year to the 2026 Senedd election, Baroness Morgan insisted she “will not stay silent” if the Westminster leadership make “decisions that we think will harm Welsh communities”.

Sir Keir Starmer’s popularity continues to fall among Welsh voters, with ITV's Barn Cymru poll revealing that the majority think he is doing a bad job as prime minister.

We asked: How well or badly do you think Keir Starmer is doing as the prime minister?

Voters said: Very well 3%; Fairly well 24%; Fairly badly 26%; Very badly 36%; Don’t know 11%.

Eluned Morgan could argue her party’s unpopularity comes largely from UK Government decision-making. However, the poll revealed just 23% of those who answered think she is doing a good job as first minister. 43% said she is performing badly, while 34% didn’t know either way.

Labour in an 'increasingly precarious position'

The Labour party in Wales is not primarily losing former supporters to Reform UK, but instead experiencing more substantial defections to other progressive parties, Dr Larner says.

He added: "The evidence parallels trends seen in England. In the Welsh context, Plaid Cymru emerges as the principal beneficiary, currently enjoying some of their strongest historical polling numbers. This shift reflects not only current dissatisfaction with both the UK and Welsh governments, but also builds upon a long-established pattern wherein Labour's Westminster voters frequently show preferences for Plaid Cymru during Senedd elections.

"Labour finds itself in an increasingly precarious position, as even a modest additional shift of their voters toward Reform UK could trigger snowballing seat losses given the narrow margins in several constituencies.

"Plaid Cymru remain well-positioned in this fragmented landscape, poised to capitalise on both anti-incumbent sentiment and their established role as the progressive alternative to Labour in Wales, with a distinct national identity appeal that neither Reform nor the Conservatives can match."

The Conservative Party suffered a wipeout in Wales at the last UK General Election and the Senedd voting intention poll puts them in fourth place, with just 13% of the vote. New Welsh Conservative leader Darren Millar has yet to make his mark, with the majority of those polled not knowing if he is performing well in the role. Just 10% said he is doing well, with 37% saying he is doing badly.

Dr Jac Larner says these results represent one of the Conservatives' poorest showings in Welsh polling over the past two decades.

He added: "Their traditional support base continues to migrate significantly toward Reform UK at both Senedd and Westminster levels.

"Reform UK will undoubtedly be encouraged by achieving their strongest ever performance in a Welsh opinion poll (exceeding even the Brexit Party's previous high watermark of 23% in 2019). These figures suggest Reform UK is positioned to establish itself as the predominant right-of-centre party appealing to the British-identifying bloc of the Welsh electorate."

Conservative leader Kemi Badenoch’s popularity has drastically fallen over the last five months, with the majority (52%) of those polled saying she is doing a bad job. Just 15% think she is doing well, while 32% don’t know either way.

ITV Cymru Wales’ survey also asked how those polled would cast their vote in a Westminster election, with Labour making losses to the benefit of Plaid Cymru and Reform UK.

Westminster voting intention

Plaid Cymru - 24%

Reform UK - 24%

Labour - 20%

Conservative - 13%

Liberal Democrats - 9%

Green - 7%

Other - 2%

• YouGov/Barn Cymru polled a representative sample of 1,265 Welsh voters, aged 16+, between April 23-30, 2025, for ITV Cymru Wales and Cardiff University.

• For the latest political debate and discussion, tune in to Sharp End, ITV Cymru Wales, at 10.45pm on Tuesday, 6 May.