The biggest legal claim ever brought in the UK over environmental pollution in the country has been filed at the High Court.

Almost 4,000 people have signed up to the lawsuit against major poultry producers and a water company over allegations of "extensive and widespread pollution" in three rivers - the Wye, Lugg and Usk.

They argue the state of the rivers in recent years has severely affected local businesses, property values and people's enjoyment of the area, and are seeking "substantial damages".