The decline of England’s rivers and coastline has bloomed like fertiliser-fed algae into a critical election issue. The government’s handling of sewage spills will affect how more than 56 per cent of people vote, according to a Survation poll. Battleground seats held by Conservatives on the coast – dubbed the “sea wall” – are particularly stinky, with Labour leading the polls this year in 108 constituencies containing a coastal town. Out of nearly 80,000 sewage spills in marginal constituencies in 2022, more than 39,000 were in Conservative seats, more than those held by any other party. One Conservative MP at risk is Geoffrey Cox, the former attorney general, whose constituency of Torridge and West Devon faced 97,000 hours of sewage being dumped into waterways in 2023.