🕒 Last Updated: 29 March 2026 – Odds and market information correct at time of last update. Political betting markets move quickly; please check with your bookmaker for current prices.
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 clearly, with Plaid Cymru at 1/5 (83.3% implied probability) and Reform UK at 3/1 (25%). Labour have drifted significantly to 33/1, implying just a 2.9% chance of finishing top, while the Greens (100/1), Conservatives (200/1) and Liberal Democrats (250/1) are all considered rank outsiders.
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’s projected collapse is stark. The party is expected to win just 12 seats, a sharp 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 the party’s history. The Conservatives are set for an equally disastrous outcome, with projections suggesting they could be reduced to just one seat. The Liberal Democrats are expected to fail to win any representation at all.
The Welsh picture mirrors the broader UK trend. Reform’s strong position in Westminster betting and Starmer’s exit date market both point to the same story of Labour under sustained pressure across the country, not just in Wales.
