An investigation discovered a faulty pipe had started to discharge anaerobic digestate into the watercourse from nearby Rotherdale Farm, which is run by the company. Officers were told that the company used a lagoon to store digestate and used an underground pump system to spread liquid as a fertiliser.

Around 220 dead fish were discovered in Piddle Brook and another 100 at a marina further down the watercourse. Farm employees said they did not maintain records of the volumes in the lagoon and had no maintenance record either of the lagoon or pipework.

A further offence was recorded in May, 2018, when company officials notified the Environment Agency that foam had been reported in Piddle Brook. An investigation revealed that sugar beet discharge, being used to irrigate a field, had started to spill into the watercourse from a faulty pipe.

No dead fish were recorded on this occasion and the farm took immediate steps to fix the faulty pipe.

The initial investigation had prompted the Environment Agency to ask the company for levels of nitrates used on the farm. Regulations were introduced in 2015 aimed at limiting the amounts of nitrogen used on land in an effort to prevent the pollution of ground and surface waters.

However, the company admitted there was no nitrogen fertiliser plan in accordance with the regulations. It was subsequently discovered that 19 fields had been treated with amounts of nitrogen that exceeded the 250kg/ha limit.

A spokesperson for the Environment Agency said: “We always strive to work with farmers to reduce the risk of pollution, protect the environment, and ensure they are compliant with the regulations. However, where there is evidence of serious pollution issues we will not hesitate to pursue the offenders concerned and take tough enforcement action.

“We expect much better from such a large and experienced farming business, both for the environment and the local community.”