Affects from the pesticide spill in Toppesfield Brook last Wednesday are now being seen as far downstream as Halstead on the R Colne.

The local news is reporting that today it reached the Causeway, in Halstead, killing thousands of roach fish, sparking fears the poison will spread to Colchester.

Environment Agency teams are still battling to rescue fish and minimise damage, but the pesticide, although now much diluted, is still persisting in the water causing fish to die after several days.

An estimated 4000 larger fish including roach, eels, perch and pike have died together with many 1000s of smaller fish. So far at least 9km of the R Colne has been affected, but this length is likely to increase over coming days.

Frank Saunders from the Environment Agency said: ‘We’re devasted to see such a significant loss of fish and invertebrates in the R Colne. We’ve been doing everything we can to minimise damage from the spill, but the amount of pesticide spilt and the type it was has meant that fish are still dying.

‘Around 3000 fish have been moved to safety, and we managed to ensure the pesticide was greatly diluted before it reached the main river, but this won’t be enough to prevent the affect on the Colne being very serious.’

With the fishing season already underway, anglers are being advised to avoid fishing the R Colne from Great Yeldham to Earls Colne. If people see fish gasping or dead anywhere along the river, please ring the Environment Agency immediately on 0845 80 70 60.

The pesticide is now very dilute and does not pose a significant risk to humans, but if anyone has been in contact with the water and is at all concerned, they should contact NHS Direct. Dog owners are being advised to keep their pets out of the water as a precautionary measure.