A WATER firm which serves five million people has been fined £600,000 for a pollution incident linked to the deaths of up 100 fish and which hit a tourism-dependent coastal village during the peak visitor season.

Yorkshire Water, which claims protecting the environment is “at the core of our day-to-day business”, also failed to act quickly to cleaning up the contamination in the Staithes area of North Yorkshire and was branded “reckless” by a judge.

Leeds Crown Court heard the firm admitted causing a water discharge activity into Dales Beck, at Dalehouse, without an environmental permit.

The fine has come as the main water utilities operating in England have come under fire by the Environment Agency for an increase in the number of major pollution incidents recorded last year.

Both Yorkshire Water and Northumbrian Water, which recorded 46 and 38 pollution incidents respectively in 2016, were found by the agency to have performed “close to or slightly below their target”.

An agency spokesman said: “Due to recent performance, we asked water companies to review and update their pollution incident reduction action plans.”

Leeds Crown Court heard the pollution originated from the firm’s Hinderwell Waste Water Treatment Works in July 2015. It had leaked from a poorly-maintained, rusting sludge storage tank.

Richard Bradley, prosecuting, said the sewage had a significant impact on the water quality in the beck. The watercourse, which passes through a caravan park, was discoloured and had a foul odour. Up to 100 dead fish were seen, and water quality tests revealed high levels of ammonia and low dissolved oxygen levels.

Downstream, the pollution incident affected water quality in Staithes Harbour, which was a designated bathing water at the time. An “abnormal situation” was declared for 17 days during the peak holiday season and Scarborough Borough Council erected signs advising the public not to enter the water.

The court heard Yorkshire Water also failed to act quickly in cleaning it up.

Judge Mushtaq Khokhar said the company had been reckless, rather than just negligent.

In mitigation, Yorkshire Water said it had invested in measures to prevent the incident recurring.