Water firms have been condemned for polluting the UK's rivers, streams and bathing waters at a rate of once week since the start of the year.

Eight out of the 10 water companies in England and Wales have been prosecuted by the agency since January and every company has been found guilty of pollution over the last 12 months.

Since the water companies were privatised they have been fined 300 times, or on averege one prosecution a month. The agency is now calling for harsher fines for the worst offenders.

On-site testing by water companies

Ed Gallagher, chief executive of the Environment Agency, "These incidences have serious financial consequences. What is the point of water companies spending millions on major new improvement works when they do no seem capable of operating them properly."

The Environment Agency highlighted some of the most damaging cases of pollution. Wessex Water has been the worst offender, being fined more than £30,000 on four separate incidents since the last year.

It was guilty of pumping more than one million tonnes of sewage into a Weymouth marina on August Bank Holiday, the busiest day of the year. The company was fined just £5,000 with £500 costs.

River Ribble was polluted after a sewer burst

North West water was prosecuted for polluting the River Ribble, putting a nearby bird resevere, one of the most important sites for native birds in Europe, in peril. One of its sewers burst sending crude sewage into the river.

Severn Trent was responsible for damaging a nature reserve in Derbyshire after polluting a stream after discharging more than 100 times the legal limit of sewage.

Water companies have been fined a total of £95,300 so far this year, an average of £4,300 for each case. The Environment Agency believes these fines are derisory compared to the hundreds of millions of pounds of profits the companies make every year and offer no incentive for the water companies to clean up their act.

Adrian Beeby: "There are always going to be soem pollution incidents"

A spokeswoman for the Environment Agency said: "The largest fine every handed out to a water company was £175,000 to Severn Trent. That was equivalent to a person earning £30,000 a year paying a fine of £5."

Adrian Beeby of Water UK: "There are always going to be some kinds of pollution incidents"

Adrian Beeby of Water UK, which represents the water industry, accused the Environment Agency of "painting a very bleak picture"

"There are always going to be some kinds of pollution incidents. We are dealing with 300,000km of sewers," said Mr Beeby.