The sewage crisis was a significant factor in the Tories’ losing support in the “blue wall” in the south of England, electoral polling suggests.

Seven out of 10 voters supported legal measures to eliminate sewage spills in ecologically sensitive areas by 2030, according to polling conducted for Greenpeace by Survation just before the election. Less than a third of voters thought the Conservatives were right to weaken their commitments on the climate crisis and the environment.

The Tories lost 37 of the 52 “blue wall” seats in the south of England, with 24 taken by the Liberal Democrats, who campaigned strongly on sewage and the crisis of polluted rivers and beaches. Some of those seats, particularly along the Thames, include spots where some of the worst sewage problems have been reported.

One in four people in the region told pollsters that the Conservative party’s stance on the environment was a key reason for not voting for them; nationally, only a fifth of people cited this as a reason.