A Carmarthenshire dairy farmer who persistently polluted a river with silage effluent has been ordered to pay fines and costs of more than £12,000.

The effluent from an overflowing silage tank at Cwrt Farm, Pentrecwrt, made the Afon Gwr Fach poisonous to fish, Llanelli Magistrates' Court was told on October 15.

The farmer, David Benjamin Huw Marks, had failed to empty the tank when needed, causing it to overflow and drain into the river on three separate occasions.

Sewage fungus was found along the 0.75km stretch of the river between the farm and where it meets the River Teifi.

The court was told that warnings and advice issued by NRW officers had not been heeded.

Marks, who pleaded guilty to offences under the Environmental Permitting Regulations 2016, was fined £6,000 and ordered to pay £6,327.10 costs and a £170 victim surcharge.

Ioan Williams, environment team leader for Natural Resources Wales (NRW), said the body supported farmers in addressing non-compliance by offering advice and practical support.

But when there was compelling evidence that regulations were being deliberately flouted, it would “not hesitate’’ to take enforcement action, he added.

Mr Williams said most farmers acted responsibly in their waste and nutrient management practices.

“We recognise that sometimes things do go wrong, but we urge farmers that if they know they have caused pollution, to report it to us at NRW immediately by calling 0300 065 3000. The sooner we know about it, the sooner we can work with them to try and reduce the impact on the environment.”