Last reviewed: 17.5.2012 - 11.13am
The proposed Thames Tunnel is the final and most challenging piece of our overall plan to tackle sewage discharges into the River Thames in London.
As the tunnel will be so deep, we've used rigs to identify the various ground conditions beneath the river
After as little as 2mm of rainfall, London's Victorian sewers which capture both sewage and rainfall can fill up and as there is nowhere else for the excess flows to go, it spills into the river from 57 combined sewer overflows, designed as an alternative to sewage backing up into homes and streets.
These sewage discharges occur up to 60 times a year on average.
Without tackling this, ten years from now the 39 million tonnes of sewage, which is currently discharged into the river in a typical year, is forecast to rise to an unthinkable 70 million tonnes.
About the tunnel
The Thames Tunnel is a sewer the width of three London buses, which will run up to 25 kilometres or 15.5 miles from west to east London, up to 67 metres below ground, broadly following the route of the River Thames.
It will connect up to the 34 most polluting sewer overflows, as identified by the Environment Agency, to capture sewage which would otherwise spill into the Thames, before transferring it to our Beckton sewage works to be treated.
Have your say
Our second phase of consultation on the Thames Tunnel launched on 4 November 2011 and closed on 10 February 2012. This phase was much more detailed than phase one, which ran from September 2010 to January 2011.
You can find out more about the project and register for updates on our consultation website.
Related documents
Case for the Thames Tunnel
Our report,‘Why does London need the Thames Tunnel?’, outlines the project’s long-term environmental, social and economic importance to the capital.
Creating a cleaner river
Watch our short film to learn what we're doing to prevent sewage entering the River Thames.
