SOUTHERN Water has been fined £18,000 after raw sewage poured into a Hampshire river for more than 33 hours, killing hundreds of fish.

The company has been prosecuted by the environment Agency after an incident last summer when a valve at a sewage treatment works developed a fault.

Sewage flowed into the Lymington River for a day-and a half before the leak was detected, New Forest magistrates were told.

The alarm was raised by a member of the public who saw dead fish in the river near Brockenhurst, the court heard.

Swimmers hoping to take a cooling dip were told to stay out of the water because it was so badly contaminated.

Environment Agency officers spent five days trying to improve conditions in the river and used a hydrogen peroxide kit to increase the amount of dissolved oxygen in the water.

Dave Robinson, environment management team leader said: "Our officers worked round the clock to prevent the situation from escalating.

"If it wasn't for their hard work we could have seen even greater damage and more dead fish.

"We did everything we could but sewage can devastate a watercourse - and this sewage was discharging for more than 33 hours.

"Had a Southern Water member of staff noticed and rectified the fault it would have prevented much of the damage."

As reported in the Daily Echo, effluent poured down a storm overflow and entered the river after a valve "froze" at a treatment works in Balmer Lawn Road, Brockenhurst.

The incident contaminated a one-mile section of the river and at one stage was thought to have killed thousands of fish.

Southern Water admitted allowing sewage to enter a controlled watercourse. As well as being fined £18,000 the company was told to pay £2,000 costs.

After the case the company's wastewater manager Nev James said: "The pollution occurred when an operative failed to notice that a valve was closed and the wastewater was being diverted into storm tanks.

"As soon as the company was made aware that wastewater had entered the watercourse it fully co-operated with the Environment Agency in flushing out the pollution.

"The company has reconfigured its alarms and replaced the valve to prevent a similar incident."