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Members of the Thames Tideway Tunnel West Section team stood in front of one of the projects' Tunnel Boring Machines

Thames Tideway Tunnel, West Section

Expanding London’s sewer network to help prevent sewage pollution in the River Thames

Customer: Bazalgette Tunnel Limited

Location: London

Value: £416m

Completion: 2025

location pin with map



in length




internal diameter



Tunnel Boring Machines used

team together



roles for people from the local area

London's 'super sewer', the Thames Tideway Tunnel is a phenomenal piece of engineering that will tackle pollution in the River Thames by collecting sewage before it enters the river, ensuring it’s properly treated and cleaning up the river for London, its inhabitants and its wildlife.

The 25 kilometre tunnel is being excavated by six giant Tunnel Boring Machines using rotating disc-shaped cutterheads, creating the tunnel walls with pre-made concrete segments whilst removing the thousands of tonnes of spoil.

The Morgan Sindall Infrastructure three-way joint venture with BAM Nuttall and Balfour Beatty is delivering the seven kilometre West section of the project, which stretches across seven sites from Acton in West London to Wandsworth in South West London.

Project fact

The Thames Tideway Tunnel is the biggest infrastructure project ever undertaken by the UK water industry

One of our project sites

"Our vision is to reconnect London with the River Thames and, by practicing what we preach, we want to demonstrate the huge potential of our city’s greatest natural asset.”

Andy Mitchell, Chief Executive Officer, Tideway

Making a difference

We are using sustainable river transport, working to reduce our carbon footprint and cleaning up the foreshore. Our joint venture has invested in two specialist tug boats, with low emission engines and low noise outputs, to contribute to a reduction in lorry movements. The tugs haul barges up and down the Thames, carrying materials to the work sites and assisting with the removal of spoil from the tunnel excavation.

Through our joint venture, 50 new apprenticeships have been created and 249 roles for people living in the local area.

Learn more

A short film about the Thames Tideway Tunnel, featuring interviews with colleagues from across the joint venture delivering the project.

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