SOUTHERN Water has been fined more than £11,000 after a burst pipe caused sewage to gush into one of Hampshire's famous chalk streams.

Fareham Magistrates' Court heard yesterday that the River Meon at Titchfield was so badly polluted that it may take several years to recover fully.

The company took more than 24 hours and spent £250,000 dealing with the leak and its aftermath after initially underestimating the scale of the problem.

The incident occurred on the evening of November 5, 2003 when a sewer near Bridge Street burst.

At first Southern Water officials presumed that a rising main sewer had burst and brought tankers in to isolate it and pump the sewage away.

The leak continued and it was not until daylight that they realised that a siphon main sewer had actually burst. It was flooding a nearby meadow and flowing into the river.

Southern Water called in a 50-ton excavator and more tankers despite being repeatedly advised that additional resources were needed hours before.

Prosecuting on behalf of the Environment Agency, Peter Bilbrough said: "The sewer could handle 650 litres per second of sewage. No one is certain of quite how much was passing through during this incident although at times it could be expected to have been near capacity. However, whatever the figure, Agency officers estimate that at one stage about two-thirds of the flow in the sewer was escaping and was getting into the river."

Samples taken from the river showed levels of ammonia six times the fatal dose for fish, and high levels of suspended solids and dissolved oxygen, which can suffocate aquatic life.

Around 100 fish were found dead the day after the leak, and a scientific expert estimated the rare brook lamprey fish species had been totally wiped out of that section of the river.

A report from the scientist said: "It may take several years before the ecology of this important ecosystem recovers fully."

The court heardthat the cast iron pipe, installed in the 1970s, had a life expectancy of 60 years and was four metres underground.

Clifford Darton, representing Southern Water, said: "What has occurred here is a one-off, unexpected event and we cannot have predicted what happened or took steps to prevent it happening."

After the verdict, regional sewerage manager Karl Taylor said: "We very much regret this incident and apologise for the effect it had on the surrounding area."

He added: The area has been reinstated and surveys taken since the incident suggest the river is recovering well."

Two days after the incident, tests revealed that the leak was caused after a tiny hole corroded in the bottom of the pipe.

Southern Water, which operates a sewerage network of more than 22,000km of public sewers, is continuing to investigate the sewer to ensure no further problems exist.