altA NEW £2 billion "super sewer" intended to stop the 2012 London Olympics site from being swamped by untreated sewage was today given the go-ahead by the Government.

 

The 18-mile tunnel - the construction of which will add £37 a year to water bills in the capital - will help stop untreated sewage from pouring into the River Thames during heavy rainfall.

 

It will also prevent sewage from backing up the Lee and Bow Back rivers, which run through the East London Olympic site.

 

The Games will be staged close to the 19th century Abbey Mills pumping station - known as the "cathedral of sewage" - which deals with the biggest overflow of sewage in the capital.

 

Approval of the new scheme comes after warnings that the Games could be ruined by the sight and smell of overflowing sewage from the City's outdated drainage system.

 

In 2005, the Thames Tideway Group, a government advisory committee, warned that there was a "100 per cent chance" of sewage overflows at the site during the summer months.

 

The new tunnel will intercept sewage and rain water discharges, and is the first major upgrade to the capital's sewage network since it was built by Joseph Bazalgette in Victorian times.

 

The new sewer will not be fully complete until 2019 or 2020, but it is hoped that, by phasing the construction of the project, the East London section will be finished to prevent a "great stink" at the Olympics.

 

The London Mayor, Ken Livingstone, has said work on the East London phase needs to start by the end of this year to be ready in time for the Games.

 

A spokeswoman for the Department of the Environment, Food and Rural Affairs (Defra) said that completing the east London part and making other upgrades by the Olympic deadline would be "challenging."

 

"We are working to coordinate a package of measures to protect the Olympic site from the risk of overflows during the 2012 Games, and any protection which can be offered by the phased construction of the tunnel will be over and above this," she said.

 

Darren Johnson, the Green party London assembly member, said work needed to start immediately to prevent the Olympics from being "blighted by raw sewage, which would be a major international embarrassment".

 

Currently, 52m cubic metres of untreated sewage pollute the Thames and Lee each year, killing fish, creating a major health hazard and damaging the "aesthetic appeal of the Thames", Defra said.

 

The inadequate state of London's sewers was exposed by a storm in August 2004, when water overflows forced billions of gallons of sewage into the Thames, killing hundreds of thousands of fish.

 

Launching the new project today, the environment minister, Ian Pearson, said the tunnel was "the right solution for London and for the environment".

 

"This will inevitably mean some extra costs for customers, but it will deliver tangible benefits for London in the long term," he added