A SEWAGE spill which closed ten miles of beach for six days could have been avoided, a court has found.

Southern Water has been found guilty of breaching the requirements of environmental permits after spilling 40 million litres of raw sewage into the sea in Worthing on September 1, 2012.

The pollution led to the closure of ten miles of beach between Lancing and Ferring.

The spill had a serious impact on local businesses, tourism and the public and could have caused long-term environmental harm, according to the Environment Agency.

Southern Water denied three breaches, was cleared of two but found guilty of a third, following a seven-day trial at Chichester Crown Court.

The company told the court blocked pumps at its East Worthing waste water treatment works were to blame for the release of the raw sewage.

The Environment Agency claimed the build-up of “ragging” – toilet tissue and sanitary products – contributed to the mechanical failure.

Southern Water said in its defence the circumstances surrounding the pollution were an “unprecedented emergency”.

Southern Water director Simon Oates said: "We acknowledge the court's decision and would like to take this opportunity to apologise to any customers or businesses who were affected by this incident.

"In September 2012, an emergency at our East Worthing treatment works meant waste water was at risk of backing up in the sewers and flooding homes and Worthing hospital. Faced with this emergency, we took the tough decision to make a controlled release of untreated waste water into the sea to protect homes and the hospital from flooding.

"At the same time, we had teams on site fixing the problem and a fleet of more than 30 tankers in the town reducing flows coming into the works.

"The Environment Agency's own water quality tests showed that the release had an 'insignificant' effect on the environment - as a result of our efforts.

"We have since invested close to £20 million on improvements at the site and installed back-up systems to help reduce the risk of a future emergency."

Chris Wick, an environment manager at the Environment Agency, said: “We are pleased that the jury agreed with us that this was an avoidable incident.

"It is very disappointing that Southern Water had a major and prolonged failure of their treatment works, particularly in such a sensitive location.

"Not only was there very real potential for significant long-term environmental harm, the incident had a serious impact on local businesses, tourism and the public as a whole following the closure of local beaches for six days.

“We take these types of incidents very seriously and will do everything within our powers to safeguard the environment and people affected, and that includes bringing those who harm the environment to account for their actions.”

A sentencing hearing is due to take place on September 18.

It is not clear what punishment the company will face.

In 2013 Southern Water was fined £200,000 for several discharges of sewage into the sea off Margate, Kent.