YouGov’s final electoral calculus for the 2026 Senedd election projects Plaid Cymru on 43 seats and Rhun Iorwerth in pole position to become the next first minister. The model leaves Plaid Cymru six seats short of a majority in the 96-member Welsh parliament.
That projection comes from fieldwork with more than 4,600 adults in Wales carried out from 25 April to 4 May. It gives Reform UK 34 seats, Labour 12, the Conservatives four and the Liberal Democrats one, while the Greens are projected to win their first representation.
Rhun Iorwerth and Plaid Cymru
Plaid Cymru’s 43-seat central projection is the highest figure in the model and places the party closest to power. The 49-seat threshold for a majority means the party would still need support from elsewhere if the projection were replicated at the ballot box.
The model’s range for Plaid Cymru runs from 36 to 48 seats. Reform UK’s projected range is 31 to 41 seats, and the party emerges as the largest in 13% of simulations. The gap between the central projection and that upper band shows how sensitive the result remains under the new system.
Labour in Ceredigion Penfro
Labour falls to 12 members of the Senedd under the model, down 32 seats on a notional comparison with 2021. The forecast puts Labour first in none of the Senedd’s 16 constituencies and gives it zero out of six seats in four constituencies, including Ceredigion Penfro.
Eluned Morgan tops Labour’s list of candidates in Ceredigion Penfro, but the model still gives the party no seats there. That is the sharpest sign in the forecast of how far the party has slipped in seats that had once been part of its wider base.
Conservatives and the Liberal Democrats
The Conservatives are projected to win four seats, down from a notional 26 in 2021. That leaves them short of the five seats needed to form a political group in the Senedd.
The Liberal Democrats are projected to win one seat, leaving Jane Dodds as the party’s sole representative. The Green result would be its first representation in the Senedd, adding another party to a chamber already set for a tighter contest at the top of the seat count.
The model’s practical implication is simple: Plaid Cymru is the party best placed to lead the next Welsh government, but the projection does not hand it a majority. Rhun Iorwerth would go into the campaign with the clearest path to first minister, while the final seat arithmetic still leaves room for a hung Senedd.
