Fuel from a petrol station has leaked into a Wiltshire river that has already been battling pollution from sewage leaks.

The River Kennet at Stonebridge Wild River Reserve in Marlborough has faced a month of contamination after a sewer lid popped open during mass flooding on January 5, causing raw sewage to pour into the river children usually play in.

After being criticised for their inaction for a month, Thames Water announced at the end of January that "a clean-up will happen in the next 72 hours."

But now, less than a month after the initial sewage leak, fuel has been spotted pouring into the chalk stream river, directly into the habitats of birds and fish.

“It was just horrendous to see the thick ribbon of fuel flowing on the surface of the river,” said Anna Forbes, senior project officer for Action for River Kennet (ARK).

“Pollution such as this has a real impact on birds and mammals that call the Kennet (a rare and fragile chalk stream) their home.

“Fuel contamination can coat and damage their feathers and fur and the toxicity will be ingested when preening.”

"This access point is where we take children into the river to learn about how special their river is. Before it was a lovely spot known for spawning wild brown trout and breeding kingfisher, today it’s a polluted mess."

The Wiltshire Gazette and Herald: The fuel travelled downstream directly into the path of feeding wildlife.The fuel travelled downstream directly into the path of feeding wildlife. (Image: ARK)

The fuel leakage was reported to the Environment Agency on Monday, January 29, by a volunteer for ARK who was able to trace the source to the Esso garage next to the river.

Footage taken on that day shows a swan feeding at Stonebridge Wild River Reserve as the fuel pollution spread downstream towards it.

The Environment Agency attended the river the day after the initial report to install a boom, a piece of material which contains the fuel and prevents any further pollution from entering the river while it is investigated.

Bridge Garage in Marlborough has been contacted for comment but is yet to respond.

“The garage has had contractors on site investigating exactly where on the site the issue stems from,” said a spokesperson for ARK.

“It’s really important to report river pollution and we urge everyone to store the Environment Agency’s pollution hotline number 0800807060 in their phones.”