A rare chalk stream that flows into the River Thames at Morden has been polluted by an oil spill.

The Environment Agency estimate that 4,000 litres entered the River Wandle yesterday afternoon.

Teams are assessing any damage to the stream and believe a storage tank at a bus depot in Thornton Heath is the source.

Pictures have emerged showing birds covered in oil and people are being told to stay away from the water and keep their dogs out of it.

In addition, people should not feed wildlife in the waterway as that will encourage them to ingest contamination.