The Environment Agency has said Thames Water ‘must take action’ to reduce sewage pollution in the River Thames after local naturalist Steve Backshall uncovered ‘horrifying’ bacteria in water samples from Marlow.

Mr Backshall, who lives on the Thames and has kayaked and canoed along it for more than 20 years, collected samples from the river downstream of the Little Marlow Sewage Treatment Works in March following over 12 hours of sewage discharge from the plant.

The discharge from Thames Water’s storm overflow system contained excess waste and rainwater that accumulated following recent heavy rainfall.

Lab results from Bangor University revealed this week that the samples contained bacterial levels tens of thousands of times higher than the acceptable concentrations and demonstrated a considerable risk of spreading E. coli, norovirus and enterovirus to local people and wildlife.

Speaking today (April 18), a spokesperson for regulator the Environment Agency described the “sewage pollution” of the waterway as “unacceptable”.

Adding: “Thames Water must take action to reduce the risk of pollution reaching the River Thames from their treatment sites.”

The River Thames in Little Marlow is not designated bathing water, meaning the Environment Agency does not monitor it for E. coli or enterococcus and cannot confirm or deny whether it is safe for water-based activities.

In a video uploaded to social media on Wednesday, Thames Water representative Andrew Scott told Mr Backshall that the high level of bacteria in the water samples did “not surprise him”.

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In response to the TV presenter asking why members of the public weren’t being warned not to go near the Thames after sewage discharges, Mr Scott said the process was “part of normal operations for sewage works”.

Adding: “We’ve got our sewage map which is available online. Anyone can log on and see when (a discharge has occurred).”

 When asked if he thought it seemed right that people have to log on each day to see whether sewage had been discharged near their homes, Mr Scott replied: “No.”

A spokesperson for Thames Water told the Free Press that “taking action to improve the health of rivers” is a key focus of the company.

They added: “While the sewage treatment process will reduce levels of bacteria returned to the environment, it’s not required as part of normal operational procedures. Processes such as ultraviolet disinfection can be introduced where needed to meet bathing water standards.

“Pollutants, animal faeces from livestock and wildlife, along with runoff from farms and roads can also contribute to hazards found in watercourses, which is why we’d recommend reading the Government’s advice on open water swimming. 

“We have experienced excessive rainfall this winter, so our storm overflow system has worked to protect customers’ homes during the wet weather by releasing diluted wastewater into rivers rather than letting it back up into people’s homes.

“We have also published plans to upgrade over 250 of our sites, including Little Marlow Sewage Treatment Works. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather.”