Press Release

Tunnel Boring Machine Charlotte completes connection tunnel drive

3 July 2020


The super sewer became one step closer to cleaning up the River Thames yesterday as tunnelling machine Charlotte completed her journey to Fulham, finishing a vital connection tunnel beneath the river.

The 1.1km connection tunnel, created at a depth of around 30 meters, will take sewage overflows from King George’s Park into the main 25km tunnel at Carnwath Road, where it will be transferred to east London for treatment instead of polluting London's waterway.

Charlotte is one of the project’s smaller Tunnel Boring Machines (TBM), measuring three metres wide and more than 70 metres long and is named after suffragist Charlotte Despard. She was the first to break through the ground to complete a section of tunnel for London’s new super sewer in October.

Having dug the 500m southern section of the Frogmore Connection Tunnel, from Dormay Street to King George’s Park, she was then hoisted from the shaft, taken back to Dormay Street and put back into the ground to tunnel the final 600m to Carnwarth Road.

With the tunnelling now complete, Ciaran McQuaid, Project Manager Shafts and Tunnels, for the western section of the project said: “It’s amazing to see Charlotte finally through into the Carnwath Road reception chamber and a big congratulations to the team for all their hard work.

“This will probably be the end of my 12 year connection with TBM Charlotte from being a Shift Engineer on her back in 2008 on the Thames Water Ring Main Extension, watching her going through her remanufacturing ready for tunnelling on Frogmore Connection Tunnel and then completing her job in style yesterday. For a TBM that is turning 26 in November and has now completed six tunnel projects, she did a great job.”

Image: Tunnelling machine Charlotte


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Vivienne Dunn
Balfour Beatty 
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Notes to editors:

  • Tideway is the company delivering the Thames Tideway Tunnel, a 25km sewer tunnel urgently required to tackle sewage pollution in the tidal River Thames. In total the project is expected to create 4,000 direct sustainable jobs. One in every 50 site jobs will be an apprenticeship. A joint venture of BAM Nuttall, Morgan Sindall and Balfour Beatty are constructing the west section of the new 25 kilometres Thames Tideway Tunnel. For more information visit
  • Balfour Beatty ( is a leading international infrastructure group. With 26,000 employees, we provide innovative and efficient infrastructure that underpins our daily lives, supports communities and enables economic growth. We finance, develop, build and maintain complex infrastructure such as transportation, power and utility systems, social and commercial buildings.
  • Our main geographies are the UK, US and Hong Kong. Over the last 111 years we have created iconic buildings and infrastructure all over the world including the London Olympics’ Aquatic Centre, Hong Kong’s first Zero Carbon building, the National Museum of the Marine Corps in the US and the Channel Tunnel Rail Link.

Vivienne Dunn

Senior Media & PR Manager