Plaid storms ahead as Labour vote collapses in Wales

A YouGov/Cardiff University survey of 2,500 adults across Wales shows Plaid on course to become the largest party in the Senedd for the first time since devolution began in 1999. Reform UK trails narrowly on 30%, while Labour and the Conservatives are tied on 10% each. The Greens rise to 9% and the Liberal Democrats to 6%.

Under the new proportional voting system debuting in May 2026, Plaid would secure 39 seats, Reform 34, Labour 10, Conservatives six, Greens four and the Lib Dems three.

Labour dominance shattered by poll shock

Labour has led every Welsh Government since 1999, but the latest figures show the party reduced to historic lows. Once the dominant force in the Welsh‑identifying progressive bloc, Labour now retains only a fraction of its former support.

Cardiff University’s analysis makes clear this isn’t voters abandoning progressive politics altogether — it’s consolidation. Plaid has absorbed the bulk of Welsh‑identifying support, while Reform has swallowed Conservative backing among British‑identifying voters.

Generational divide drives realignment

The raw data reveals a stark split by age. Plaid dominates among younger voters, winning 37% of 18–24s and 31% of 25–34s. Reform surges among older voters, taking 31% of those aged 55–64 and 30% of those aged 65–74. Labour barely registers across all age groups, peaking at just 10%.

Education tells a similar story. Plaid is strongest among graduates, while Reform leads among those with no qualifications.

Voters say why they’re switching

Plaid supporters overwhelmingly cite “standing up for Wales” as their reason for switching, with nearly half of respondents choosing that option. A further fifth back Plaid tactically as “best placed to stop Reform UK.”

Reform voters are driven by immigration, with 42% saying it is the party’s defining issue. Nigel Farage’s leadership remains a powerful draw, with nearly one in five citing him as the only leader who understands ordinary people’s problems.

What it means for Wales

The poll does not provide constituency‑level figures, but the national trend is clear: Labour’s grip on Wales has loosened dramatically. Even in traditional strongholds, the party’s dominance can no longer be taken for granted.

If these figures hold, Welsh politics faces a generational realignment. For the first time in a century, Labour faces the prospect of opposition or junior coalition status, while Plaid Cymru is poised to lead the Senedd.