Thames Tunnel

Project overview

What is the Thames Tunnel?

The Thames Tunnel is a proposed 25km sewer tunnel which would run underneath London from Acton in the west to the Beckton Sewage Treatment Works in the east. It would roughly follow the route of the River Thames.

The tunnel would be connected to approximately 34 'combined sewer overflows' (CSOs) which currently release raw sewage into the Thames after heavy rain fall. The proposed tunnel would intercept these sewage discharges and transfer them to the Beckton Sewage Treatment Works. The aim is to improve water quality in the Thames.

The project would involve creating six construction sites in Wandsworth, and others close to the borough boundary including one at Barn Elms (Richmond).

The scheme is being developed by Thames Water.

Why is it needed?

Sewage regularly overflows into the river from the capital's Victorian sewerage system. The current network of major sewers, founded 150 years ago, is no longer big enough to meet the needs of modern day London .

In a typical year, the city's sewers discharge 39 million cubic metres of untreated sewage into the River Thames. Mixed with rainwater, the sewage content of the discharges ranges from ten to 90 per cent.

If pollution levels in the Thames are not brought down then British taxpayers could face significant EU fines. The Thames Tunnel is the Government's preferred solution for reducing these sewage discharges and meeting EU water quality targets.

Phase one consultation

In September 2010 Thames Water published its original plans for the Thames Tunnel scheme and opened the phase one public consultation. Wandsworth Council's full response to the consultation is available online or a view brief summary.

Phase two consultation

In November 2011 Thames Water published revised plans for the Thames Tunnel and opened the scheme's second round consultation. The updated proposals included a series of important changes negotiated by the council. A summary of these changes and the council's concerns - the council's full response to phase two consultation is also available online.

Application submitted

Thames Water's development consent application was accepted for examination by the Planning Inspectorate on 27 March 2013. As a major infrastructure project the application will be determined by the Planning Inspectorate, not by local councils.


The Examination formally commenced on 12 September 2013. The Planning Inspectorate appointed a team of five inspectors, chaired by Jan Bessell, who will form the Examining Authority. Hearings commenced on 11 November and continued intermittently to 21 February. Full recordings of the hearing sessions are available on the Planning Inspectorate website.

During the Examination, the Examining Authority also issued three sets of questions with response deadlines on 4 November 2013, 13 January 2014, and 3 March 2014. The Council’s responses are available on the Planning Inspectorate website.

In addition the Council also produced a Local Impact Report, which it submitted to the Examining Authority on 4 November 2013. Final submissions to the Examining Authority were required by 3 March 2014.

The Examination closed on the 12 March 2014. Thames Water requested an extension of the Examination for a further two months which was declined by the Secretary of State. More detail on the Examination process and access to all the submissions made to the Examining Authority can be found on its website.

Thames Water's website includes useful links to 'summary information' for the six Wandsworth sites plus Barn Elms. The full documentation is also available for scrutiny via the Inspectorate's website.

Save Barn Elms campaign

One of the most significant changes from the original plans is that Barn Elms Playing Fields is no longer a mains drive shaft site. Find out more about the campaign to save this popular greenfield sports venue.

Who will pay for it?

The cost of the scheme would be added to household water bills in the Thames Water region - this includes every household in Wandsworth. Wandsworth Council has campaigned for a cap to be placed on the total amount local people will pay for the scheme if costs overrun. In March 2012 the Government passed a new piece of legislation which would limit the amount household water bills increase to pay for the scheme.