Plaid Cymru are on course for a historic breakthrough in the 2026 Senedd election, according to the latest YouGov MRP model, with projections pointing to a dramatic shift in Welsh politics and heavy losses for Labour and the Conservatives.
Senedd Election Odds:
| Party | Odds | Implied Probability |
|---|---|---|
| Plaid Cymru | 1/5 | 83.3% |
| Reform UK | 3/1 | 25.0% |
| Labour | 33/1 | 2.9% |
| Greens | 100/1 | 1.0% |
| Conservatives | 200/1 | 0.5% |
| Liberal Democrats | 250/1 | 0.4% |
The betting markets reflect this shift, with Plaid Cymru now clear favourites to win the most seats at 1/5, giving them an implied probability of 83.3%.
Reform UK follow at 3/1 with a 25.0% chance, while Labour have drifted significantly to 33/1, implying just a 2.9% chance of finishing top.
The Greens are priced at 100/1, with the Conservatives at 200/1 and the Liberal Democrats at 250/1, highlighting how unlikely it is that any of the traditional parties will lead the next Senedd.
The model places Rhun ap Iorwerth firmly on track to become the next First Minister, with Plaid Cymru projected to win 43 seats in the expanded 96-member Senedd. That would leave them just six seats short of an overall majority and mark the first time the party has topped a national election in Wales.
Reform UK are also expected to make a major impact, with projections suggesting they could secure around 30 seats and finish comfortably in second place. The Greens are forecast to win 10 seats, which would represent a significant breakthrough given they have never previously had representation in Cardiff Bay.
Labour, by contrast, are facing a dramatic collapse.
The party is projected to win just 12 seats, a huge drop that would end decades of political dominance in Wales. Having led every major election in the country since 1922, such a result would represent one of the most significant declines in its history.
The Conservatives are also set for a disastrous outcome, with projections suggesting they could be reduced to just one seat, while the Liberal Democrats are expected to fail to win any representation at all.
