A Cornwall farmer has been ordered to pay £3,765 after a digestate spill at his farm caused a major fish kill in the River Ottery. Truro magistrates’ court heard that Norman Osborne, 57, of Tobarn, Jacobstow, operated the farm near Warbstow where the pollution incident took place in 2022. Following a hearing on 13 May, Osborne was fined £215 after pleading guilty to causing a water discharge activity. He was also ordered to pay £3,550 in costs to the Environment Agency, bringing the total to £3,765.

The Environment Agency said officers were called on 22 May 2022 after reports of dead fish in the River Ottery. Their investigation found that about 2,300 gallons of digestate had entered the watercourse from a tank on Osborne’s farm. The court heard that Osborne had been transferring digestate from a tank to a tanker for spreading on farmland when a connecting hose broke. The spill then ran down the road and into a nearby watercourse. The damage was made worse when the spilled material was washed into the watercourse, and the incident was not reported to the Environment Agency at the time.

Digestate is widely used in farming as a fertiliser, but the case is a sharp reminder that it can become a serious pollutant when storage and handling fail. The Environment Agency described it as a wet, slurry-like material produced through the anaerobic digestion of food and other organic waste, with very high ammonia and nitrogen levels. In the River Ottery, the consequences were immediate and severe. Some 3.5km of watercourse was affected. Investigators found sludge and microplastics in the water, and the pollution is understood to have driven ammonia levels high enough to cause a large-scale fish kill.

A total of 471 dead fish were counted, but the true number was estimated at 1,610. The losses included Atlantic salmon, brown trout and bullheads, species that help show the health of a river system and are part of the ecological fabric of Cornish catchments. What stands out most is not only the scale of the mortality, but the slow recovery. The court heard that even two years after the incident, fish populations had still not returned to historic levels. For a small river, that points to damage that lingers well beyond the initial spill.

The Environment Agency said Osborne’s failure to report the incident quickly added to the harm, because early contact can allow regulators to advise on containment and limit further damage. That point matters. Once polluted material has moved through a watercourse, the window for reducing ecological loss narrows fast. The penalty will prompt debate about whether current sanctions match the real cost of freshwater pollution. A £215 fine, even with costs added, looks modest beside the loss of wildlife and the length of river affected. Still, the prosecution makes one point clearly: preventable farm pollution is not a minor paperwork issue when a river is left struggling years later.

There is also a practical lesson here for farms using digestate as part of more circular waste and nutrient systems. Digestate can help return nutrients to land, but only when tanks, hoses and transfer routines are robust enough to keep that material out of streams and rivers. For regulators and land managers alike, this case is a case for tighter checks on equipment, clearer emergency plans and faster reporting when things go wrong. For communities that care about river health, it is another sign that recovery depends not only on cleaning up after pollution, but on stopping avoidable spills before they start.