Wildlife coated in oil after 4,000-litre spill from London bus depot into River Wandle

A coot covered in oil near the River Wandle - (Bobby Dean/X)

Wildlife have been coated in oil after an estimated 4,000 litres spilled into a rare chalk stream in London, officials have said.

The Environment Agency said the oil had spilled into surface water drains and affected the River Wandle, a once-heavily industrialised chalk stream that has been revived and is now home to wildlife such as brown trout to kingfishers.

It is expected that the spill, thought to have come from a storage tank at a nearby bus depot, will affect the Wandle from Beddington to Wandsworth over the coming days.

Residents have reported to me an environmental disaster on the Wandle today.

A major diesel spillage has left wildlife covered and caused untold damage to the waterway.

I'm in touch with the Environment Agency and will make sure those responsible are held to account. pic.twitter.com/E0E4mj2SaX

— Bobby Dean MP 🔶 (@Bobby_Dean) February 18, 2025

A spokesperson for the environment agency said: “On receiving reports of an oil spill on the River Wandle, officers were immediately deployed to limit damage to the local environment and working with the London Fire Brigade we have put in place measures to stop the leak.”

“We are currently gathering evidence and assessing the environmental impact for our investigation, with the pollution source suspected to be a bus depot storage tank in Thornton Heath, Croydon.”

The Wandle flows through south London

The Wandle, which flows for nine miles from its source to the Thames, became heavily industrialised from the 17th to 19th centuries, suffering from severe pollution.

For many years the waterway was considered “ecologically dead”, according to the South East Rivers Trust, but there has been a considerable effort to clean up the river and it is now a popular walking trail.

It is home to brown trout, a key chalk stream species, which was re-introduced to the river, while the Wandle and surrounding habitats support wildlife including kingfishers, damselflies and bats.

Chalk streams are a globally rare habitat, most of which are in England, and face a range of threats including climate change, over abstraction of water and pollution from sources including farming, urban run-off and sewage.