Thames fined £4m for “foreseeable and avoidable” sewage spill

Thames Water has been fined £4m with more than £90,000 in costs for discharging some 500,000 litres of raw sewage into two streams in Oxford in July 2016 in a “foreseeable and avoidable” incident.

The Environment Agency reported that the 30-hour discharge into the Seacourt and Hinksey streams flowed for at least 3.5km along the waterways killing some 3,000 fish.

The court heard how the company had failed to carry out essential maintenance to prevent blockages in a sewer that it knew to be vulnerable to blockages. Thames, the agency said had relied, “not for the first time,” on observations by members of the public to spot blockages and sewage releases. The incident was reported to the Environment Agency by canoeists.

The court also heard that the water company had failed to adequately maintain the high risk section of sewer for at least 16 years. Also it heard how Thames had failed to comply with a requirement to maintain a six-monthly regime of documented, cleaning of the sewer to prevent blockages.

The Environment Agency had previously issued Thames Water with two formal warnings following earlier pollution from the same discharge point following earlier blockages in February and March 2012.

The court was told how the water company failed to disclose highly relevant documents, including a maintenance manual, until the 11th hour and only after members of the public had brought one of them to the attention of the Environment Agency.

Environment Agency senior officer, Robert Davis added: "This fine sends out a clear warning to the boards of all water companies – invest heavily in maintaining your sewers and don’t drop the ball when it comes to carrying out that maintenance."

The conviction brings the total amount of fines levied against Thames Water since 2017 to £32.4 million for 11 cases of water pollution across Oxfordshire, Berkshire and Buckinghamshire. See Minister numbers fines for sewage spills since 2018 .

• Thames latest conviction followed launches by the Environment Agency and Ofwat of investigations into sewage treatment works after checks led to water company admissions that they could be releasing unpermitted sewage discharges. “Any company caught breaching their permits could face a range of possible enforcement action – up to and including prosecution,” the agency warned.