UNITED Utilities has been fined £10,000 after a stretch of water became polluted following a leak of raw sewage.

The pollution was discharged into a tributary of the River Ribble near Clitheroe as a result of a sequence of problems at the Knuck Knowles pumping station.

Anglers at Brungerley Bridge alerted the Environment Agency to the leak on September 24 last year.

Investigations revealed that household waste dumped down drains and toilets had clogged up the pumps, causing an overflow of sewage. Yesterday, Hyndburn Magistrates' Court heard how the unmanned pumping station is regulated by a computer alarm system and that four days prior to the leak the system software was being updated as a result of an overflow nine months previously. During this maintenance work the computers crashed and failed to restart properly, leaving the system off-line and unable to report the clogged pumps.

Representing the region's water provider, United Utilities, John Hunter said that if the system had been working staff would have been able to respond to the overflow problem immediately.

Mr Hunter added: "The company works hard to protect the environment. It was an unfortunate by-product of our ethics that led to this."

United Utilities pleaded guilty to discharging sewage into the water, contrary to the Water Resources Act 1991.

Five dead fish were found following the leak, indicating a rapid drop in water quality and oxygen levels. A thin film of sewage fungus was also found coating rocks nearby.

Jane Morgan, representing the Environment Agency, said that United Utilities appeared to have worked hard to solve the problem. A new alarm system is now in place, staff have been given additional training and residents have been sent leaflets instructing them not to throw household rubbish into the sewage system.

The company was fined £10,000 and ordered to pay costs of £2,928.