Ananova:

The Environment Agency is taking emergency action to clean a major pollution spill on a tributary of an important salmon river.

Tens of thousands of gallons of slurry have poured into the River Dart, a tributary of the River Exe, near Tiverton, Devon, which provides drinking water for Exeter and is the home to salmon.

Agency teams are pumping polluted water out of the river and are using hydrogen peroxide to try to restore its oxygen levels.

Martin Weiler, spokesman for the Environment Agency, said the pollution is still many hours away from reaching the River Exe. But he said staff would be working through the night to try to clear the slurry from a six-mile long section of the River Dart.

Below stream of the polluted water, fish are being stunned and removed from the river.

"We are taking emergency action to try to stem the damage and minimise the potential effects to the main River Exe," he said. "The real threat is if all the oxygen gets starved from the river and we are concerned about the effects on the fish."

The incident was first reported to the Environment Agency in the morning but the full scale of the pollution only emerged later in the afternoon.

Mr Weiler said he still did not know what the full environmental impact could be.

"The amount of pollutant is significant," he said. "It is possibly tens of thousands of gallons. It is a major incident and it does have the potential to cause environmental damage."

He said staff believed they had traced the source of the pollution - a slurry store on a nearby farm - and he said a full investigation would be carried out into the incident.