The River Nene. Picture: Pat Ringham

THOUSANDS of fish died and thousands more were harmed by 5,000 litres of agricultural chemicals that leaked into the River Nene in Peterborough last June, magistrates heard.

Some of the fish were bleached and others leapt from the water and died along the affected 30 mile stretch of water.

Chemical manufacturer and packaging company Safapac pleaded guilty at Peterborough Magistrates’ Court on Tuesday to causing the pollution on June 18 2012 but claimed the leak was caused by vandals who damaged containers.

The case has been sent to the crown court for sentence as magistrates felt their sentencing powers were insufficient.

The leak released an insecticide, fungicide and disinfectant into the river.

All three chemicals are very toxic to aquatic organisms and can cause burns, drowsiness or dizziness to people.

The effect on the River Nene was seen as far as Wisbech and cockle fishing in The Wash was quarantined and closed from June 19-21 by the regulatory authority.

Peterborough and District Angling Association had to cancel fishing matches and members also cancelled because of the pollution, costing the club £928.

Two cockle fishermen claimed they lost more than £10,000.

The pollution’s total cost to the members of the Greater Wash Fishing Industries Group was estimated to be £216,772.