Eighty-three per cent of English rivers contain evidence of high pollution caused by sewage and agricultural waste, according to the largest citizen science water testing project ever to take place in the UK.

Hundreds of anglers took part in the study, organised by the Angling Trust, after being angered by the brown blooms of sewage in the waters they painstakingly tend for the benefit of fish.

Six hundred and forty-one anglers from 240 angling clubs now regularly monitor pollution in 190 rivers across 60 catchments. Between them, they have taken more than 3,800 samples, which are revealing the systemic pollution across England’s waterways. This is mainly caused by agricultural runoff and sewage spilled by water companies.