Hundreds of litres of toxic red diesel has spilled into the River Wandle.

Environment Agency officers have been struggling to contain a oil spill which could devastate wildlife in the river, after it was reported by construction workers working at de-culverting the waterway in Wandle Park.

Despite the speedy response the oil has spread for more than a mile downstream and has been reported in Beddington Park.

Peter Ehmann, who is co-ordinating the clean-up for the environment agency, said: “It was really good that the council contractors acted so fast, at has averted something that could have been much worse.

“If it had gone all the way down the river it could have had a very serious impact on both the aquatic and waterfowl wildlife of the Wandle.”

He said the Wandle collects runoff from across the Croydon area, which was making discovering the source difficult, and feared the oil could still be flowing into the river.

He said: “We are appealing for help from anyone for the source of the pollution. The flow seems to have lessened but we can not be sure it has stopped.”

Waterbirds such as ducks and swans are particularly at risk. If the diesel gets on their plumage they are liable to try and lick themselves clean, ingesting the toxic fuel.

The team, using floating booms, have managed to prevent much of the oil floating downstream and are using a tanker to suck it away.

The EA has launched a full investigation even as cleaning efforts continue and surveys of the affected stretch of river will take place to assess the impact of any ecological impact over the coming weeks.

Members of the public with any information on the incident can call the Environment Agency’s 24 hour hotline on 0800 807060