The River Thames is one of the cleanest metropolitan rivers in the world, home to 120 species of fish and aquatic life. However, without the vision of the Victorians, who designed the sewer system that still serves London today, things would have been so much different. Now, 150 years on, the next phase of the evolution of the sewers is about to begin.
Exactly 150 years ago to the day, all London's sewage was being flushed directly into the Thames every day - around 149 million tonnes a year. Cholera and typhoid were striking down Londoners in their thousands. On a blazing summer day, the stench from the Thames was so overpowering that MPs vacated a committee room because of the 'great stink'. Amid uproar in the Commons, Parliament was suspended and Members demanded action.
In less than two months, Parliament had passed an enabling Act to raise the GBP3 million to build a network of giant intercepting sewers and pumping stations. The plans were the brainchild of one of the greatest engineers of the Victorian age, Joseph Bazalgette, who is today credited for helping to banish cholera and save the lives of tens of thousands in the process.


The sewers still serve London today, together with later additions, including treatment works. But the combined pressures of population growth, climate change and changing lifestyles are now putting the system under strain.

Imagine the population of London flushing their toilet at the same time. Now multiply this by 850. That's the amount of dilute sewage currently swept into the Thames every year, representing 32 million tonnes.
David Owens, Chief Executive of Thames Water, which treats all of London's sewage and manages the network of thousands of miles of sewers, said that London's sewers are one of the great engineering wonders of the Victorian age, and have served us well for 150 years. Bazalgette designed them to overflow into the River Thames during occasional heavy storms and although this had an environmental impact on the river, the alternative of letting sewage overflow into homes and streets, was unthinkable. "The Government has given the go-ahead for us to build the Thames Tideway Tunnel (yellow line on the map at the right, Ed), a massive intercepting sewer, running from Hammersmith in West London, to Beckton in the east. Earlier this month we submitted plans for the smaller Lee Tunnel, which will intercept sewage overflows into the River Lee. Together with our GBP400million programme of investment to improve our major sewage treatment works, this marks the final step in Bazalgette's grand plan and will help us deliver a sewage system for London fit for the 21st Century and beyond."


Boris Johnson, Mayor of London said that on the anniversary of the 'Great Stink', it is an opportune time to look ahead to how we ensure London is never again forced to deal with such extreme consequences of sewage in the Thames. The swift progression of the Thames Tideway sewer is vital to avoid the dumping of raw sewage into the capital's river, jeopardising our health, polluting wildlife and damaging the recreational use of the Thames. Future generations of Londoners will thank us for taking forward this bold vision, in the same way that we are remembering Joseph Bazalgette today.

Clive Coley, of the Environment Agency, added that the Great Stink taught us a valuable lesson about what can happen when we abuse our environment. “We have worked hard to improve the river for people and wildlife over many years. Once the Tideway Tunnel is in operation, we can truly say that our worldclass capital has 21 Century sewage system and a river that can be enjoyed to its full potential."