UK's biggest ever environmental pollution claim reaches High Court

“That just isn’t what this river should look like and feel like and smell like,” Ms Evans, a wildlife filmmaker, told BBC News on the banks of the Wye, not far from her home. “There’s been systemic failure going on. And so in light of that, it seemed like the only course of action is to take legal action and make polluters pay.”

Campaigners have long pointed at the rapid expansion of industrial chicken farming near the River Wye. At present there are about 24 million chickens being raised in the catchment area – usually in huge sheds. That’s about a quarter of the UK’s entire chicken population.

Until recently manure from the Wye’s chicken sheds was spread as cheap fertiliser on nearby arable farmers’ fields. The group legal claim alleges that the nutrients from the manure frequently washed off the soil into waterways leading to high levels of phosphorus, nitrogen and bacteria entering the rivers. In warm weather that nutrient load caused the water to turn green, so called “algal blooming”.

In 2023, Natural England, the UK government’s official advisory body, rated the condition of the River Wye as “unfavourable — declining”. The follow-up River Wye Action Plan in 2024 blamed excessive nutrients from farming and wastewater discharges as well as climate change for increasing the water temperature and reducing the water flow in hot dry summers.

Legal firm Leigh Day is bringing the case on a no-win no-fee basis. They say that although it was arable farmers who spread the manure, Avara Foods and its subsidiary Freemans of Newent should be held responsible for the consequences.

“The poultry companies that are being sued in this claim knew what the outcome of their operations were going to be when they expanded the poultry production in this area,” Celine O’Donovan, one of the Leigh Day lawyers, told BBC News.

“As a result, the responsibility for the decline of these rivers needs to lie with the people that knew what was going to happen and have made the money from it and controlled the supply chain that resulted in it.”