Raw sewage was seen by coun Tony Fisher, a former physics teacher, across the Bank Holiday weekend in the River Foss, Strensall, following a period of heavy rain.

Coun Fisher said he has previously seen condoms, toilet paper and sanitary products in the river just seven miles north east of York city centre.

He described Yorkshire Water’s inaction on sewage being discharged into rivers as “disgusting” and even suggested it may be a contributory factor towards fish deaths, despite the Environment Agency saying they were caused by a combination of high temperatures and thunderstorms creating a lack of oxygen in the water.

Coun Tony Fisher said: “It is shocking that Yorkshire Water has denied that previous incidents of sewage dumping have contributed to the death of fish in York.

“We have now seen first-hand Yorkshire Water’s active pollution of the River Foss.

“We now need to see urgent action from Yorkshire Water to make sure incidents like this do not happen again.”

Coun Paul Healey said: “During the periods of heavy rain we saw over the bank holiday weekend we saw that the Victorian combined sewage system couldn’t cope with the excess surface water that entered the system and raw sewage pumped out.

“This type of raw sewage discharge is a real danger to the health of not only residents but also the wildlife and fish that can be seen in the Foss.

“Yorkshire Water continues to ignore calls to improve the sewage network despite recording record profits last year.”

A Yorkshire Water spokesperson said: “During periods of heavy rainfall, such as those experienced in Strensall over the Bank Holiday weekend, when treatment works and pumping stations are working at full capacity, storm overflows act as a relief valve to prevent wastewater backing up in the network and causing sewage escapes in people’s homes, businesses and gardens.

“These are permitted by the Environment Agency.

“However, we know there is more to do to reduce overflows into Yorkshire’s rivers.

“Tackling storm overflows is a priority for us and we’re already working on our largest ever environmental investment as part of our 2025-2030 business plan.

“The plans, which will be subject to approval by our regulator Ofwat, outline a £1 billion investment to further reduce discharges from overflows to meet the government’s storm overflow reduction plan.”

Sewage systems in the UK date back to Victorian times and when heavy rainfall occurs the sewage can discharge into rivers to stop streets and houses flooding.

But this has led to an increase in water pollution and while water companies such as Yorkshire Water make hundreds of millions of pounds profit, some think more of those profits should go into keeping rivers clean.

A 2022 House of Commons Committee report on the state of UK rivers shows no rivers in England were free from chemical contamination, while only 14 per cent of UK rivers had a “good” ecological status.

Foss from the Syke to the River Ouse Water Body has a moderate rating.

River Foss sewage: Yorkshire Water told to “clean its act up” after sewage spotted in River Foss