Labour is level with the Tories, also on 10%, while the Greens are one point behind on 9% and the Lib Dems take 6%.

Plaid are projected to have 39 seats, Reform 34 and Labour down to 10. The Conservatives are estimated to have six, the Greens four and the Lib Dems three.

It would be a damaging blow to Sir Keir Starmer as he faces mounting questions over his leadership ahead of the local elections which are expected to be a bloodbath for his party.

A Reform UK Wales spokesman said: “It’s clear to everybody here in Wales that the next Senedd election will be a two-horse race between Reform and Plaid.

“With Plaid, Wales will get more of the same extreme policies that we’ve had from Plaid and Labour working in tandem in Cardiff Bay.

“Meanwhile, Reform will be fighting to restore common sense to Welsh politics, and to deliver real change for our communities here in Wales.”

A Plaid Cymru spokesman added: “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.”