A wastewater treatment works in Keswick discharged raw sewage for more than 8,000 hours last year - the second longest period for any plant in England.

Figures published by the Environment Agency (EA) revealed that untreated sewage was discharged into England’s waterways for a total of 3.1 million hours in 2020 through storm overflow pipes.

The Environment Agency allows water utilities to release sewage into rivers and streams after extreme weather events such as prolonged heavy rain.

This protects properties from flooding and prevents sewage from backing up into streets and homes.

According to the data, sewage spills increased by 27 per cent in 2020, with 403,171 last year compared to 292,864 in 2019.

However, the EA attributed the increase to a “higher number of overflows being monitored”.

Increased monitoring will provide a clearer image of the scale of sewage pollution, as the number of overflows monitored now stands at 12,093, up 32 per cent from 8,276 in 2019, the regulator said. Average spill numbers remained similar to last year, it maintained.

Figures shows that the longest overall spill duration for a single plant was at United Utilities’ Sedburgh wastewater treatment works, which discharged for 8,490 hours.

The second longest was a United Utilities’ plant at Keswick, which discharged for 8,275 hours.

However, United Utilities have disputed the Environment Agency's figures, saying they relate to a combined sewer overflow which was removed in February 2020.

Tony Lywood, who represents Keswick on Cumbria County Council, said that the town's flood risk was likely an issue but that water companies should be held to account for releasing sewage into waterways.

He said: "Keswick does suffer from significant flooding which is blatantly an issue, although in the last couple of years we haven't had any major flooding.

"My view is the water companies need to be brought into line to make them much more responsible for the environmental impact.

"For example, they're not responsible for flooding mitigation at all.

"I would like to see much stricter controls on water companies releasing sewage into any river if it hasn't been treated. Secondly, I would like to see them brought back into public ownership."

Lynne Jones OBE, chair of Keswick Flood Action Group, said: "It's utterly disgusting.

"The water industry is one of the most heavily regulated of all and yet water companies continue to pollute.

"If they get away with that, how are we ever going to get any progress over flood risk management?

"This is just a complete mess. Our environment is being polluted in the most appalling way. It's shameful."

David Burn, Keswick town councillor, said: The Lake District was awarded World Heritage Site status in 2017.

"The town has about 5,000 residents, about 20million tourists a year visit the Lake District. Many of them come to Keswick to experience the fantastic scenery and enjoy the area’s excellent facilities.

"Against this backdrop it is hard to believe that United Utilities are discharging raw sewage into our local waterways.

"I don’t know precisely where this is being done but many residents and visitors swim in Derwentwater and our local rivers - to think that some of the areas they may be swimming contain sewage is frankly disgusting.

"I believe the Government plans to introduce legislation compelling water companies to reduce the impact of these discharges - and not before time.

"The government also needs to introduce legislation compelling water companies to build flood prevention measures into their plans."

A spokesman for United Utilities said: : “The data referenced is incorrect, as it relates to a combined sewer overflow which was removed in February 2020.

"There have been no discharges at all at this location since then. We have identified this as part of our wider programme to assess anomalies with the data from some of our spill monitors and the Environment Agency is aware of this.

"When the data assessment exercise is complete we will update our published data.”