AN MP has spoken of his "deep concern" at the discharge of raw sewage which has been pouring into a tributary of the River Thames for weeks.

Witney MP Robert Courts wrote to Thames Water to express concern at continuous releases into the River Windrush from Witney sewage treatment works.

Sewage was released into the river at Witney every day from Christmas Day with the last discharge on January 9.

Treatment works are allowed to release sewage into waterways after wet weather and when they are close to capacity, but Mr Courts said river levels in West Oxfordshire were currently at normal levels.

In a letter to the water company's CEO Sarah Bentley, posted to Mr Courts' Facebook page, the MP wrote: "Sewage releases are currently permitted when there are exceptional rainfall events, albeit for a limited time going forward given the recent legislation in the Environment Act.

"Yet the river levels in West Oxfordshire are all currently at or within their normal levels. Therefore, rather than this being an 'extreme measure', it appears that Thames Water are treating 'storming' as a routine process. This is clearly unacceptable to my constituents."

He added: "[I am] deeply concerned at reports that Thames Water has been routinely releasing sewage from Witney Sewage Treatment Works over the last couple of weeks when we have not experienced any heavy rainfall.

"I have written to the Chief Executive of Thames Water to demand an explanation for these spills, which highlight just how vital it is for the expansion of Witney [sewage treatment works] to be delivered urgently.

"I am also following up with the Environment Agency to ask them to investigate whether these spills breach Thames Water's permit conditions. I have been clear that illegal spills which harm our environment must be punished in the strongest possible terms."

Following an alert given in a tweet earlier this month, foraging group Oxfordshire Wild commented: "Super poopers! Impressive 16 day streak from Thames Water."

Wild swimmers in Oxford are planning a protest on Port Meadow on Sunday January 23 to put pressure on Thames Water to invest in improved infrastructure after festive swims were cancelled because of the releases.

In October 2020 Mr Courts came under fire for voting down an amendment to the Environment Bill that sought to stop companies pumping raw sewage into waterways.

The amendment, which was first put forward by the Duke of Wellington in the House of Lords, proposed forcing large companies, such as Thames Water, to ‘take all reasonable steps’ to avoid sewage overflowing into rivers.

Most Conservative MPs, including Mr Courts, voted against the amendment and it was voted down. Mr Courts said the main reason it was not accepted was because it came with no plan and no impact assessment of how it could be implemented.

He did support a plan to reduce storm overflows.

Thames Water’s own figures record that in 2019 its treatment plant at Witney pumped raw sewage into the Colwell Brook and Windrush for a total of 1,395 hours.

The figures for 2020 show a rise from that to 1,563 hours into the river that eventually passes by Ducklington Lake.

Ash Smith of campaigning group Windrush Against Sewage Pollution (WASP) said: "We like the idea that Mr Courts is showing some interest in the subject but to be effective he needs to look at where the problems still lie, and that is mainly in Government-led prosecution policy and resourcing which stifles Environment Agency action and makes pollution profitable.

"Unfortunately, as we saw in the voting and as he explained to us earlier in 2021 when he was unable to support a private member's bill, it is very hard for a government Minister to go off the Government script even if his constituency would benefit if he did.

"It would be helpful if he spoke to WASP to get up to speed but has not accepted our offers to brief him on a rapidly developing subject."

A Thames Water spokesperson said: “We’re aware of Mr Courts’ letter and understand the serious concerns about the discharges from Witney STW (sewage treatment works).

“We’re working as fast as possible on a major upgrade at Witney, which will provide at least 40 per cent more treatment capacity. In the meantime the site team are doing everything they can to minimise discharges from the site.”

The company said an upgrade to the Witney plant was fully funded in its current business plan and it had recently appointed contractor Tilbury Douglas, with which it was finalising a design. The completion date is likely to be early in 2024, but they are continuing to look for ways to bring this forward into 2023.

The spokesperson added: "At Witney STW, the current minimum flow that is required (by the site’s permit) to be passed to full treatment is 240 litres per second, but the site team are working hard to get the best possible performance from the works and are consistently achieving more than 260 per second."