Tideway publishes latest Annual Report detailing pivotal year for River Thames
Tideway, the company building London’s super sewer, has published its latest annual report and accounts, detailing a year in which the new infrastructure began protecting the River Thames for the first time.
The new tunnel system adds more than a billion-and-a-half litres of capacity to the existing sewerage network and will protect the Thames from sewage pollution.
The report details a pivotal 12 months for the project, in which the system was brought ‘online’ in sequence, and was fully connected in February. Soon after, His Majesty The King visited the project to mark the milestone.
Tideway CEO Andy Mitchell said: “This has been a landmark year for Tideway – the moment we moved from building to protecting. After years of construction under London, the tunnel is now doing its job.
"Seeing the data on flows through the tunnel – the volumes being diverted away from the Thames – is hugely rewarding. It’s a clear sign that this vital piece of infrastructure is doing exactly what it was built to do: protect London’s most important natural asset.
"The super sewer is now playing a critical role in the long-term health of the Thames and, by extension, the health and wellbeing of Londoners.”
To date, the Thames Tideway Tunnel, as the super sewer is formally known, has captured more than seven million tonnes of sewage pollution that would otherwise have spilled into the River Thames.
Since the tunnel was fully connected in February, there have been zero sewage discharges from the spill points to which Tideway connected the new infrastructure.
Tideway Chair Michael Queen said: “For almost a decade, the Tideway team has been working toward its foundational mission – protect the tidal Thames from sewage pollution. This year, that mission has been accomplished, and it’s thanks to the tens of thousands of individuals that have worked on this project that we are where we are.
“While there remains work to do – not least, testing the system in a range of storm conditions, and finishing the above-ground public spaces – this is a moment of transition for Tideway the company.
“Having been immersed in the construction phase for many years, we are now looking ahead to our future as an asset ownership company, as well as the bright future that has now dawned for the health of the River Thames.”
The latest report also outlines how the cost of the project to billpayers remains within the estimated range set out more than ten years ago, as well the timeline for full completion ahead of the regulated 2027 date.
It also reveals that more than 40 million work hours from over 25,000 people have been contributed toward the project – still without a single major injury (or worse) since work began in 2016.
You can read the Annual Report below, or you can download the report by clicking here.
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Work on the Tideway project began in 2016 – with activity taking place at two dozen construction sites from Acton in west London to Abbey Mills Pumping Station in Stratford, east London.
More than 20 deep shafts – some as wide as the dome of St Paul’s Cathedral – were constructed across London to divert sewage flows and to lower tunnelling machines into the ground.
The first of these giant machines started work deep beneath London in 2018, with primary tunnelling on the 25km main tunnel and two smaller connection tunnels completed in 2022.
By the autumn of 2023, a secondary tunnel lining was fully complete on all the tunnels, with the heavy civil engineering work then completed in the spring of 2024, and full connection reached in 2025.
The Tideway project was delivered by an alliance of contractors. The west region was delivered by a joint venture of BAM Nuttall, Morgan Sindall Infrastructure and Balfour Beatty. The central region was delivered by a joint venture of Ferrovial Agroman UK and Laing O'Rourke. The east region was delivered by a joint venture of Costain, Vinci Construction Grands Projets and Bachy Soletanche.
System integration was delivered by Amey, who were responsible for providing process control, communication equipment and software systems for operation, maintenance and reporting across the Thames Tideway Tunnel system.
ENDS