The discharge of chlorinated water over a month led to the discovery of 434 dead fish in one day.

Yorkshire Water has been ordered to pay more than £900,000 after polluting a watercourse with millions of litres of chlorinated water, causing the death of hundreds of fish.

Sheffield Magistrates’ Court heard how the firm’s Ingbirchworth Water Treatment Works, near Barnsley, discharged intermittently into the freshwater watercourse linking Ingbirchworth and Scout Dike reservoirs for almost a month.

District Judge Tim Spruce said Yorkshire Water had shown a high degree of negligence, resulting in “a prolonged and catastrophic loss of aquatic life”.