Scandal of Thames sewage

A furious row has broken out over the decision to deliberately poison the Thames with raw sewage, killing tens of thousands of fish and other aquatic species.

Up to one million tons of sewage was pumped into the river by Thames Water to stop the waste being pushed out into streets and homes as London was hit by a torrential downpour on Tuesday.

Critics said the discharge, which has devastated fish stocks, had been "a disaster waiting to happen" following decades of failure to invest in London's sewerage network.

The environmental catastrophe for the Thames exposed the woefully inadequate system. The Environment Agency revealed that a total of 20 million tons of untreated waste is routinely pumped into the river each year. It said even moderately heavy rainfall overwhelms the sewerage system an average 60 times a year.

Experts are warning swimmers, rowers and pleasure boat users to stay away from the Thames for at least the next few days amid concerns for human health from "very high" levels of bacteria. The worst pollution incident in the Thames for nearly two decades has killed tens of thousands of fish, including adult carp up to 10lb in weight, along a long stretch of the river around Kew, Isleworth and Brentford. It could take four years for fish stocks to recover fully.

Thames Water insisted it had no alternative following the dramatic cloud burst that overwhelmed the drains.

The company said the sewage would have flooded thousands of homes with disastrous consequences if it had not been diverted into the river.

The row came as Thames Water got the goahead for a 16 per cent increase in water bills, far short of the 40 per cent hike it had sought to pay for investment in the capital's crumbling system. Environment Agency officials described the pollution as an ecological disaster. Steve Colclough, an expert on estuaries who researches fish stocks in the river for the agency, said: "I would say it could take up to two years for fish stocks to recover based on what we've see so far.

"But this is not the end of the incident and it could take up to three or four years for the river to recover.

"To the untutored eye it might look there is nothing wrong but at the bottom of the river are thousands of dead fish."

Mr Colclough said it will not be until next summer's spawning season when his team of researchers will be able to truly assess the impact of the pollution. "This has been a major incident, there's no doubt about that."

A mix of solid faecal matter, paper, condoms, and even hypodermic syringes flowed for hours into the river after the storm. Currents and tides means that it could be three months before the "sewage slick" finally drains into the sea at Southend.

The disaster was caused by rainwater filling sewerage pipes and "blocking" the system so that the raw sewage could not reach the huge treatment plants at Beckton in east London and Crossness in Thamesmead.

That meant Thames Water managers were forced to open the 58 sewage outflows that line the river so the pipes could be drained before the filthy water began rising up through manhole covers in the streets.

Around 650,000 tons was measured going into the river from pumping stations at Hammersmith, Weston and Lot's Road in Chelsea, while an estimated 300,000 to 400,000 tons drained through other outflows.

Senior Environment Agency officials said Thames Water's actions highlighted the inadequacy of the capital's ageing sewerage system.

The agency's technical manager John Goddard said the massive discharge was only an extreme example of what was happening on a weekly basis.

He said: "When there is even moderate rainfall of just a few millimetres the system fills to capacity and nothing can get through to Beckton and Crossness.

"What we had was quite a severe rainfall event but discharges happen 50 or 60 times a year with up to 20 million tons of untreated sewage going into the river.

"How can you have a major capital city with 20 million tons of sewage running through its main river every year when we are supposed to be setting an example to the cities in the developing world?"

He called on the water regulator Ofwat to allow Thames Water to raise bills even further to fund the ?1billion cost of a giant "Interceptor" drainage channel to prevent future poisoning of the Thames.

He said research by the agency suggested consumers would be happy to pay for the investment through their bills, which are the lowest in Britain.

The 20-mile long pipe would run under the Thames and be used as a gigantic drainage duct for rainwater and sewage in stormy weather. The alternative is to "dig up every street in London" to install separate rainwater and sewerage pipes, he said.

Most other major cities with comparable sewerage systems, including Chicago and Milwaukee, had already built an "Interceptor" style pipe.

However, Peter Bowler, a campaigner with the consumer group WaterWatch, savaged decades of inaction by Government and the water industry.

He said: "This was a disaster waiting to happen. Thames Water has known for ages that the sewer overflow system was not up to the job.

"This is a problem of a company run for profit rather than for the sake of customers or the environment. It all goes back to privatisation.

"If Thames Water can't run the system properly without fleecing the customers then the Government should do what it did to Railtrack and take it back."

A spokesman for Thames Water said: "The system worked in the way that it was supposed to but everyone agrees that what we have now is not a long-term solution. Something else has to be put in its place."