London's 150-year-old sewer system was built for a population less than half its current size. As a result, millions of tonnes of raw sewage spills, untreated, into the River Thames each year during rainfall.
The Thames Tideway Tunnel has been designed to increase the capacity of the sewage system for future generations.
The tunnel is being built by Tideway on behalf of Thames Water. It is expected to be completed in 2025 and protect the river for at least the next 100 years.
The main tunnel construction site in Southwark is at Chambers Wharf on Chambers Street. The site has existing planning permission for four residential buildings. Ownership will go back to a developer to build them once the tunnel is complete.
You can find out more about the Chambers Wharf site on the Tideway website.