Election insights: Latest Senedd modelling
31st March 2026
Grasshopper have input the latest Senedd opinion polling (YouGov, 24th March) into their probabilistic model in order to update their aggregated polling data.
Find out more about Grasshopper’s polling model here
Dr Andy Cotter-Roberts, Head of Research & Insight, said:
“Our modelling shows that support for Reform UK and The Greens appears to be stabilising.”
“However, the Labour vote is still experiencing big fluctuations.”

“Most notable is the fact that, as we get close to the election, vote distribution now shows far fewer contests for the sixth MS in numerous constituencies.”
“Whereas before the data was showing us that Reform and the Greens were going head to head for the sixth MS in six different constituencies, that has now shifted.”
“As a result, we are now seeing a battle between the Greens and Labour for the sixth MS in three constituencies.”

Craig Lawton, Head of Corporate Affairs, said:
“These battles remain critical.”
“Whoever wins these- Labour or the Greens- could well be in poll position to secure support for their manifesto asks in any coalition or agreement with Plaid Cymru.”
“Importantly, this news also suggests that whilst Reform are certainly going to do well in this election, they appear to not be securing any additional support.”
Grasshopper’s latest polling analysis shows that the seats where the Greens and Labour are now going head to head for the sixth MS are:
- Clwyd
- Blaenau Gwent Caerffili Rhymni
- Sir Fynwy Torfaen
