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Mayor of Wandsworth sends off ‘super sewer’ tunnelling machine on her 1km journey under Wandsworth

Mayor of Wandsworth, Cllr Piers McCausland, and Mayoress Elizabeth McCausland at our Dormay Street site

The Mayor of Wandsworth visited one of the ‘super sewer’ construction sites to send off a tunnelling machine digging a 1km tunnel under Wandsworth to help tackle sewage pollution in the River Thames.

The three-metre-wide refurbished tunnel boring machine (TBM), named Charlotte after suffragist Charlotte Despard, started digging the Frogmore Connection Tunnel from Tideway’s Dormay Street site yesterday afternoon (26 March).

When the project is complete in 2025*, the 1.1km tunnel will take sewage overflows from King George’s Park into the main 25km Thames Tideway Tunnel at Fulham, where it will be transferred to east London for treatment.

The Mayor of Wandsworth, Cllr Piers McCausland visited the Dormay Street site last Thursday with the Mayoress, Elizabeth McCausland. He said: “The new tunnel will pick up sewage and take it to be treated, rather than polluting the river, which is great for the environment and certainly a huge improvement. I think that’s of great benefit to the people of Wandsworth and the people of London.”

Ciaran McQuaid, Project Manager for Shafts and Tunnels at Tideway, said: “While our tunnel is a bit smaller than the main super sewer, it will play a vital role in helping to clean up the River Thames by helping to stop around 100,000 tonnes of sewage ending up in the river. The team is really looking forward to getting to work on tunnelling and getting Charlotte to King George’s Park later in the year.”

Charlotte will tunnel at around 25m deep, travelling 500m from Dormay Street to King George’s Park. She will then be transported back to Dormay Street and tunnel another 600m under the River Thames to connect to the main tunnel at Tideway’s Carnwath Road site later this year.

Instead of building a new machine from scratch, Tideway is using a refurbished TBM that has been used on seven projects, including a Thames Water project in north London.

Kevin Dollard, Section Manager on the Frogmore Connection Tunnel, said: “Because of the dimensions of the tunnel, we were able to refurbish one of Morgan Sindall’s Tunnel Boring Machines instead of building a new one from scratch, testament to our approach towards sustainability and the circular economy. Some of our team have even worked on the TBM before on other projects, and are looking forward to seeing the machine up and running again to build a new, important piece of infrastructure.”

The refurbished Lovatt machine, originally built in Canada, has been given a female name as is tradition with tunnelling machines. Charlotte is named after Charlotte Despard - a key leader in the Suffragette movement and political activist who lived in Wandsworth and spent much of her time doing charitable work in Battersea.

Another TBM also launched from Battersea last week, and is named Ursula after Audrey ‘Ursula’ Smith, a British cryobiologist at King’s College Hospital. She joins Millicent, named after suffragist Millicent Fawcett, who was the first Tideway TBM to start tunnelling in November last year.

Notes to editors

Tideway is building the Thames Tideway Tunnel, a 25km sewer tunnel to prevent the current tens of millions of tonnes of raw sewage that pollute the river every year. With 24 construction sites from Acton in west London to Beckton in east London, construction began in 2016 and the project is due for completion by 2025*. The west section of the Thames Tideway Tunnel is being delivered by a joint venture of BAM Nuttall, Morgan Sindall and Balfour Beatty. For more information visit


*This article has been amended to reflect the project's updated completion date following an analysis of the impacts of the pandemic.  

Charlotte TBM factory visit