Super sewer drives its way through London passing underneath 21 bridges  

A giant tunnel has this week been dug under the final bridge in London before completion.  

On 26/10/2020 the TBM Ursula, named after the British cryobiologist Dr Audrey Ursula Smith,  passed underneath Tower Bridge marking the last passage under the 21st bridge over the Thames as it works from west to east, with 19km of tunnel now constructed.  

The 25km super sewer, which will clean up the tens of millions of tons of sewage that currently pollute the River Thames, has had its outer tunnel shell built underneath west and central London and will soon start its final phase of digging in the east.  

Tideway has been using huge TBMs since 2018, with a number of sections of the tunnel already having their first stage complete. Once the outer shell is in place, the team then line its concrete segments with an inner layer of concrete, in a process called secondary lining. Details of the other five TBMs being used to create the super sewer and clean up the River Thames are available here.  

Ursula will finish her journey at the Chambers Wharf site in Bermondsey, marking 7.6km of tunnelling from where she picked up the job in Battersea, using 4,227 concrete segments to form the tunnel. Two other machines have already completed the first stage of tunnelling from Battersea to Acton, and the most easterly section from Bermondsey to Stratford will start soon. 

The central section of the project, between Fulham and Bermondsey, is being jointly delivered by contractors Ferrovial and Laing O’Rourke.  The project is due for completion in 2025. For archive information please click here and uk/54 and also find further information by visiting https://www.tideway.london/. 44/20.