A water firm has been ordered to pay nearly £19,000 after a sewage discharge killed hundreds of fish.

Southern Water was fined £13,500 and ordered to pay a further £5,406 in costs by Sevenoaks magistrates after the overspill between September 23 and 24 this year.

The Environment Agency was called in after a member of the public reported seeing dead and dying fish in the Hammer Stream at Hammer Mill Farm, Biddenden.

When an officer arrived he saw fish gasping for air near the firm's Cranbrook site.

A survey found 275 dead fish in the area near the works, including bullhead, stone loach and sticklebacks.

It was found the company had exceeded agreed limits for sewage set by the Environment Agency.

These allow for some sewage to be discharged during heavy rainfall - when the treatment works can't cope - and the flow in the incoming sewers is more than 30 litres per second.

But on September 26 it was found that rainfall had not exceeded that agreed limit.

Ben Tragett, senior environment officer, said: "The discharge seems to have been caused due to a blockage at the works.

"Alarms on the systems there should identify when this happens.

"These alarms are electronically connected to Southern Water Services' control room in Worthing and their activation should have resulted in a response from the defendant company as they indicated a discharge to the environment.

"In fact not only was there no response, but the defendant company were apparently unaware of the discharge until after we visited the site on September 26."

He added: "We will not tolerate this sort of incident. We expect companies handling raw sewage to take their responsibilities very seriously and, while we would rather work with them to sort these problems as early as possible, we are prepared to take legal action when such breaches occur."