Green party analysis shared with the Guardian suggests Labour could lose up to 50 seats to the Greens at the next general election if the government approves new North Sea oil and gas drilling or fails to prioritise urgent climate action. The research, based on polling of key Labour-Green marginal constituencies, indicates that affected voters want bolder climate policy following a summer of record heatwaves, wildfires and drought across the UK, and that Labour MPs risk being punished at the ballot box if these demands go unmet.

Among those said to be at risk is Louise Haigh, an ally of Prime Minister Andy Burnham. The Greens, led in this analysis by deputy leader Rachel Millward, oppose new licences for projects including the Jackdaw gasfield and the Rosebank oilfield west of Shetland, with decisions on both expected in the coming weeks. Burnham has said he intends to be "pragmatic" on oil and gas, while Labour has dismissed the Green claims, noting that the number of seats projected to go to the Greens has fallen from 20 to seven since he took office. Some Labour MPs are reportedly uneasy about backing expanded drilling, arguing it would boost oil company profits without improving energy security or cutting bills.