In the summer of 1858, London had a smell problem that even Parliament could not ignore.
For decades, the city's sewage had been pouring into the River Thames. In June 1858, a stretch of hot weather turned the river into something close to an open sewer. The stench was so strong that it came to be called the Great Stink.
The Houses of Parliament stand right on the riverbank, and members found it hard to get any work done. Within weeks, legislation had passed that would lead to one of the most important public health projects of the nineteenth century.
How London got here
London grew enormously in the first half of the 1800s. By 1851, the census counted about 2.4 million people in the metropolitan area.
Through most of that period, much of the city's human waste ended up in cesspits beneath houses. Night-soil men emptied them, and they often leaked. From the 1840s on, a newer technology, the flushing toilet, became more common. That was an improvement in one sense, but the toilets were connected to sewers that emptied directly into the Thames. Around the same time, the rules were changed so that houses had to connect to the sewers.
As a result, more and more sewage flowed straight into the river. The Thames was also where many of the water companies drew the city's drinking water.
Cholera
London went through several cholera epidemics in the mid-1800s, including in 1832, 1848 to 1849 and 1853 to 1854. Tens of thousands of people died.
At the time, many experts subscribed to miasma theory, the idea that diseases such as cholera spread through bad air. The physician John Snow disagreed. During the 1854 outbreak in Soho, he mapped the cases and traced many of them to a single water pump on Broad Street. His work pointed to contaminated water as the way cholera spread. At first, few people accepted his ideas.
The odd twist is that the sewer system was built largely because people believed in miasma. They thought the smell itself was what made people sick. The remedy they paid for, getting the sewage out of the river, also happened to stop cholera from spreading through the water.
The summer of 1858
June 1858 was very hot. The low, warm river sat baking in the sun. Contemporary reports describe a smell so overpowering that people stayed away from the river entirely.
In Parliament, curtains were soaked in chloride of lime, a disinfectant, in an attempt to keep the smell out. There was talk of holding sittings somewhere else. The newspapers had a field day, and Punch ran cartoons depicting the Thames as a filthy, monstrous figure.
The smell gave the problem a political urgency that years of disease had failed to produce. Within about eighteen days, Parliament passed legislation giving the Metropolitan Board of Works the authority and the financing to fix it.
Joseph Bazalgette
The chief engineer of the Metropolitan Board of Works was Joseph Bazalgette. He had already drawn up plans for a new sewer system, and now he had both the money and the mandate to build it.
His plan called for large intercepting sewers running parallel to the Thames on both banks. They would collect the sewage from the old sewers that drained into the river and carry it east, downstream of the city. There it would be released into the Thames on the ebb tide, away from where people lived.
The project included:
- Around 82 miles of main intercepting sewers, with more than 1,000 miles of street sewers connected to them.
- Pumping stations, among them Abbey Mills in the east and Crossness on the south bank, which raised the sewage so it could keep flowing by gravity.
- The Thames Embankments, including the Victoria Embankment, built in part to carry the low-level sewers. The embankments also reclaimed land from the river and made room for new roads, gardens and an underground railway line.
A famous engineering choice
Bazalgette is often given credit for making the sewer pipes far larger than the population of the time strictly required. He is said to have doubled the planned diameter, on the reasoning that the pipes would only be built once and that the city would keep growing. Whether or not the story is told exactly as it happened, the system's large capacity goes a long way toward explaining why it served London well into the twentieth century.
Did it work?
The main system was largely finished by the mid-1870s. London's last major cholera outbreak, in 1866, hit mainly East London, in an area that had not yet been connected to the new system. After that, cholera never returned to London as an epidemic.
The river itself still had problems. Sewage was still being dumped into the Thames downstream, and it took many more decades of improvements in treatment before the river became much cleaner.
The Thames Tideway Tunnel
Bazalgette designed his system to overflow into the Thames during heavy rain so that the system itself would be protected. As London's population grew by millions beyond what he had planned for, those overflows became frequent. By the early 2000s, tens of millions of tonnes of untreated sewage were entering the tidal Thames in a typical year.
The answer was the Thames Tideway Tunnel, a new 25-kilometer "super sewer" running under the river and designed to catch most of those overflows. Construction started in the 2010s, and the tunnel was brought into operation in 2024 and 2025. In a sense, it is a sequel to the Great Stink.
What the record supports
- The hot summer of 1858 and the smell are well documented in newspapers, parliamentary records and letters.
- The speed of the legislation is a matter of record.
- Bazalgette's design is documented in the Board's reports and in his own papers.
- The story about doubling the pipe size is widely repeated and plausible. It comes from biographical accounts rather than from a single dated document.
- The cholera connection was not fully understood at the time. Snow's work was vindicated later.
Why it matters
The Great Stink shows that big public works often happen only once a problem becomes impossible for the people in charge to ignore. It is also a case of the right fix coming from the wrong theory. And it is a reminder that infrastructure is never really finished, since every generation has to maintain and extend what it inherits.
Sources
- Stephen Halliday, The Great Stink of London: Sir Joseph Bazalgette and the Cleansing of the Victorian Metropolis (Sutton Publishing, 1999).
- UK Parliament, "The Great Stink," Living Heritage section of parliament.uk.
- Science Museum Group, materials on Joseph Bazalgette and London's sewers.
- John Snow, On the Mode of Communication of Cholera (2nd edition, 1855).
- Tideway (Bazalgette Tunnel Ltd), Thames Tideway Tunnel project information.