All tunnelling work has been completed on London’s super sewer, the Thames Tideway, which is due to be completed in 2025.
Work began in 2018 for the 25km tunnel that runs from east to west London and is up to 70 metres deep under the capital.
Environment minister Rebecca Pow said: “It is wonderful to see this project reaching this important milestone; it’s a phenomenal feat of British engineering and will deliver huge environmental benefits for the River Thames. The Tunnel will prevent millions of tonnes of sewage overflowing into the river, helping to improve water quality and allowing marine life to thrive further. Our partnership with Tideway has been an extraordinary success and I want to thank all those involved for their hard work on this incredible project, and I look forward to seeing its completion.”
To commemorate the landmark stage in the project a performance by musician Rob Lewis was held at the deepest part of the sewer system.
As the project nears its completion date of 2025, work remains to be done on a secondary lining, connection and testing works.
Tideway, the company delivering the tunnel, is financed by Bazalgette Tunnel Limited, which in turn is owned by a consortium of investors. The project is being funded from water bills under the regulatory asset base model that is also being introduced for new nuclear projects.
In March, Ofwat changed the licence for the project to reflect the impact of Covid-19 pandemic on costs and the fall in interest rates since the project began. Customers will absorb a greater proportion of the additional costs relating to work being suspended at the start of lockdown but will no longer be exposed to changes in interest rates.