Green light given for London's 'super sewer'

The 25km tunnel will run underground from Acton storm tanks in West London, and travel roughly the line underneath the river to Abbey Mills Pumping Station in East London, where it will connect to the Lee Tunnel.

The sewage collected from the 34 most polluting discharge points along the tidal river in Central London, will then be taken via the Lee Tunnel to Beckton sewage works for treatment.

Last year, 55Mt of sewage polluted the tidal River Thames, far higher than the average 39Mt that discharges in a typical year. This was due to the exceptionally wet weather, which caused the combined sewerage system that London has, collecting rain water and sewerage water from drains, to fill up and pour into the river even more than normal.

With the weather of 2014 already proving to be wetter than a typical year, the amount of sewage that is going into the river is likely to once again be above average.

"If the tunnel had been in operation last year, it would have captured 97 per cent of the sewage that poured in to London's river," said Andy Mitchell, chief executive of Thames Tideway Tunnel. "Hardly a week goes by when untreated sewage isn't pouring in to London's river and we are pleased that we can now start to tackle this archaic problem.

"This is a huge project but it's a huge problem, and we can now get on with tackling it. It's no easy task, but we're confident that we can deliver this project and still achieve our aim of minimising the impact on our customer bills."

The Thames Tideway Tunnel will take seven years to build, and main construction can now start in 2016 as planned.

The project has been given a Development Consent Order (DCO), by the Government, to be built as proposed using 24 construction sites across London. It will involve using six tunnel boring machines from five drive sites and will directly create more than 4,000 jobs.

Mitchell added: "This DCO means we can improve London's river for the benefit of Britain. We appreciate the impact our construction work will have on some communities near our sites, but we will continue to work with them to keep disruption to a minimum."

The Thames Tideway Tunnel will be financed and delivered by an independent specialist company, separate to Thames Water and with its own licence from Ofwat. Interested investors are currently preparing bids, with the successful bidder expected to be announced next summer.