Thames Water investigation after blue substance kills river fish

Thames Water is investigating a toxic blue substance which is reportedly killing fish in a south London river.

Residents reported pollution at the Chaffinch Brook in Lewisham, on the River Pool, on 13 September.

Scores of dead fish washed up on the banks of the river, which feeds in to the River Ravensbourne, according to reports on social media.

Thames Water said it has worked with the Environment Agency to limit the damage to local wildlife.

A Thames Water spokesperson told the Local Democracy Reporter Service: "We have worked with the Environment Agency, our pollution team and engineers to limit its effects, which were caused by a blue-coloured substance entering the local river."

"Due to colour and odour of the substance," Thames Water believe the pollution came from a third party.

A "point of entry" in the river has been identified, the company said.

Inflatable barriers have been installed along the water course and tankers used to "pump out polluted water" into Thames Water's treatment centres.

"These clean-up efforts, as well as recent rainfall, have cleared the polluting flow from our system," the spokesperson added.

Rushey Green Councillor James-J Walsh praised the efforts of Thames Water and the Environment Agency, describing it as an "impressive response".

He said: "Good to know they're there to protect life and natural habitats."

The Environment Agency has been contacted for comment.