Toxic Algae Prompts Thames Swim Ban at Ham and Kingston
Environment Agency extends warning as blue-green algae discovered near Thames Water's Hogsmill plant, raising infrastructure concerns.
Image: Eddie Pollard / AI
Sarah Connor
A do not swim warning has been issued at London's only Thames bathing spot in Ham and Kingston.
The Environment Agency confirmed a dire warning: toxic blue-green algae, cyanobacteria, now infests the water.
"Bathing is not advised, due to pollution from harmful algae," an Environment Agency spokesperson stated. "We have identified blue-green algae on the lower River Thames including the Ham and Kingston designated bathing water."
Environment Agency officers actively sample water along the river; the warning stretches across the Thames between Hampton and Kingston.
Local abstractors downstream and the UK Health Security Agency received immediate notification.
The algae thrives in warm, calm, dry weather; consecutive record-breaking heatwaves are believed by Marlene Lawrence to be behind the water pollution.
Bathing is not advised, due to pollution from harmful algae.
Cyanobacteria can produce toxins that reportedly cause skin rashes and illness in humans, and are potentially fatal to pets and wildlife.
Thames Water’s Hogsmill sewage treatment plant sits just three miles upstream of the Ham bathing site.
Thames Water has postponed over 100 projects, including an upgrade to the Hogsmill works, now unlikely until 2028.
The regulator, Ofwat, investigates the failure to upgrade the Hogsmill infrastructure.
The algae discovery raises further questions about Thames Water's plans to pump 75m litres of treated sewage a day into the river near the bathing spot.
Campaigners argue this proposed recycling project would provide only 75m litres of water daily, placing immense environmental pressure on the river.
This amount is reportedly a mere fraction of the 570m litres of water the company leaks every day.
An Environment Agency spokesperson emphasized the danger: "It is important that members of public do not enter the Thames along this stretch. It is also vitally important to keep dogs out of the water."
A recent assessment, conducted under retained EU legislation, revealed only 14% of England's rivers, lakes, and coastal waters are in good ecological health, evaluating 4,658 surface water bodies.
The report attributes these widespread issues to sewage spills, agricultural nutrient runoff, and pollutants from urban areas and roads.