THREE-QUARTERS of Britain’s rivers are in poor ecological health, largely thanks to pollution from water companies, a new study led by citizen scientists found today.

More than 2,600 people across Britain went out and measured the water quality of their local rivers as part of a mass campaign organised by environmental charity Earthwatch Europe.

From the samples collected, the charity found that rivers in Thames and Anglia were in the worst state, with 89 per cent in poor ecological health. 

Hertfordshire and Cambridgeshire had the worst water quality, with 91 per cent and 89 per cent showing “unacceptable” levels of nutrient pollution.

The samples were tested for nitrate and phosphate, which are normally present in domestic and industrial waste and sewage,  as well as in fertilisers that wash off farmland.

Dr Sasha Woods, the charity’s director of science and policy, said: “These results are truly disturbing — there are no parts of the UK unaffected by nutrient pollution.

“The picture around London and the Thames river basin is particularly dire.

“Our rivers have been historically stressed by farming, and we’re seeing this being made worse by inappropriate or limited sewage treatment.”

Last month, the Office for Environmental Protection said legal targets to improve water health were going to be missed by a “considerable margin” and could see just 21 per cent of surface waters in a good ecological state by 2027.

Only 16 per cent of water bodies are in a good state, according to official Water Framework Directive monitoring.