Bacteria warning at Wolvercote Thames swimming spot

Wolvercote Mill Stream on the River Thames was granted bathing water status by Defra in April

The only official swimming spot on the Thames has "extremely high bacteria" levels downstream of sewage treatment works, a study has shown.

Published by the Environment Agency, the survey showed E Coli and Intestinal Enterococci in the water at Wolvercote Mill Stream, in Oxford, at levels higher than is safe for swimming.

Campaign group Thames21 called for upgrades to two sewage plants.

Thames Water said all discharges were "fully treated".

The popular swimming spot, two miles from Oxford City Centre, was granted bathing water status by Defra in April after an 18-month campaign by local swimmers opposed to raw sewage discharges.

The status means the river water at the site is tested weekly for harmful bacteria by the Environment Agency between May and September.

'Not surprised'

The results from the summer of 2022 showed intestinal enterococci, with levels more than twice the recommended amount.

Thames Water has stated it plans to halve raw sewage spills by 2030.

Thames21 project officer Claire Robertson said it was "disappointed but not surprised" that the utility firm had not committed to upgrading treatment works at Cassington or Stanton Harcourt, despite high bacteria levels downstream.

She said: "This is not nearly fast enough for the swimmers and paddlers at Wolvercote, many of them families with young children, nor for the wildlife and plants that call this part of the Thames their home. We need action now."

Richard Aylard, Thames Water sustainability director, said: "All sewage discharged from Cassington Sewage Treatment Works since April 2021 has been fully treated.

"While the sewage treatment process is not designed to remove bacteria, we recognise the concerns raised regarding the presence of bacteria in the river which can come from multiple sources."