Building resilience in water, from the riverbed-up

Resilience isn’t built in boardrooms or policy papers – it’s built into the very foundations of the infrastructure projects we’re delivering.

For hundreds of years, the River Thames has been a symbol of prosperity for London, acting as a vital artery for trade and business as part of the ever-evolving heartbeat of the nation’s capital.

Yet, underground, an unseen challenge was brewing; an overstretched, outdated Victorian sewerage system that was struggling to keep pace with modern demands, a growing population and increasingly unpredictable weather patterns.

That challenge has now been met head-on. Last month, London’s super sewer, Tideway London was successfully activated. The last of 21 connections was made between the original Victorian sewers and the new 25km-long Thames Tideway Tunnel, bringing the entire system online to protect the tidal Thames from sewage pollution. 

And it’s working. Since the first of the connections were made, more than 6,375,000m³ of sewage has been captured and prevented from entering the river. That’s the equivalent of 2,500 Olympic-sized swimming pools, which, if laid out in a row would stretch from London to Birmingham. 

The Thames Tideway Tunnel is not only solving a 150-year-old problem, it will provide London with resilience well into the next century.

As Tideway's CEO Andy Mitchell CBE said at the time: “We are at the start of a new chapter for London and its river. Our mission has always been about creating not just a tunnel, but a healthier, thriving environment for the river and its inhabitants.”

It’s difficult to get across the enormity of this project – particularly because much of the actual construction has taken place below ground level. And it’s crucial to realise that no single organisation could have achieved this vision alone. Indeed, the project was delivered by legions of contractors, engineers and construction workers across three regions operating under different joint ventures. Costain Group PLC , as part of a joint venture with VINCI Construction Grands Projets and Bachy Soletanche , delivered the east section of the scheme.

London is now benefitting from cleaner, safer, and healthier river water, and the UK construction sector can tap into an enormous volume of knowledge and skills that have been gained over the last decade. The project has started and nurtured careers, driven social mobility, created thousands of jobs, and set new standards for safety, innovation and sustainability.

Beyond the environmental wins and the skills gained, Tideway tells a bigger story: one of resilience. It's a model example of how strategic, long-term infrastructure can help communities thrive and safeguard the planet. Not for the first time, I’ve seen first-hand how the UK can be a world leader in delivering transformative ‘mega’ projects, whether it’s the Channel Tunnel or the Thames Barrier.

The common factor behind any successful delivery of critical national infrastructure is the public and private sectors working together. In the case of Tideway, water companies, businesses, regulators, local and national governments have all pulled together to achieve something greater than the sum of its parts. We already know the UK is full of talented workers with the knowledge, tools, skills and talent to rise to any challenge, but problems arise when groups don’t work together effectively. This collaborative, enterprise mindset must be retained.

As we strive to create a more resilient UK in the face of rising demand and climate change, the industry must take stock of the lessons learned from Tideway and apply them to future projects. Investing in next-generation infrastructure – whether that’s reservoirs, renewable energy or high-speed railway systems – isn’t about papering over the cracks and fixing historic issues; it’s about predicting and pre-empting future challenges, and ensuring the UK prevents those challenges from becoming reality.

Tideway is a shining example of what the UK is capable of when innovation, sustainability, and long-term thinking come together. It’s unquestionably a remarkable feat of engineering. The Thames Tideway Tunnel is not only solving a 150-year-old problem, it will provide London with resilience well into the next century. It shows how infrastructure can shape a greener, more sustainable and cleaner future.