In the hot, rainless June of 1858, the British Parliament came close to being driven out of its brand-new Palace of Westminster — not by plague, fire or revolution, but by smell. The Thames, which lapped against the building's terrace, had become an open sewer, and that summer's heat cooked it. Curtains on the river side of the palace were soaked in chloride of lime in a doomed attempt to mask the stench; committees abandoned their rooms; Benjamin Disraeli, fleeing one sitting with his papers in hand, described the river as a "Stygian pool". The newspapers gave the episode the name it has kept ever since: the Great Stink.
The crisis had been decades in the making. London's population had roughly trebled since 1800, past two and a half million, and the fashionable new flushing water closets had made matters worse, not better: instead of collecting in cesspools, waste now poured through old drains straight into the Thames — the same river from which several water companies drew drinking supplies. Cholera returned again and again: epidemics in 1831–32, 1848–49 and 1853–54 killed tens of thousands of Londoners. Nearly everyone, including the great sanitary reformers, blamed "miasma" — disease carried on foul air. The physician John Snow argued in 1854, after mapping deaths around a single water pump in Broad Street, Soho, that cholera travelled in water instead. He was politely ignored.
What evidence could not do to official opinion, the smell did to Parliament in a fortnight. With the river unbreathable outside their own windows, MPs passed a bill in just eighteen days that gave the Metropolitan Board of Works the money and powers to cleanse the Thames. The board's chief engineer was Joseph Bazalgette, the meticulous, workaholic grandson of a French immigrant, and what he built remains one of the largest engineering projects ever undertaken inside a living city.
Eighty-two miles of interception
Bazalgette's scheme did not try to rebuild London's chaotic drains; it intercepted them. Great new sewers were driven from west to east across the city — three main lines north of the river, two south — catching the flow of the old drains before it could reach the Thames and carrying it by gravity to outfalls far downstream. In all, the works comprised 82 miles of main intercepting sewers fed by roughly 1,100 miles of street sewers, built from some 318 million bricks and vast quantities of Portland cement, then a novel material that Bazalgette trusted precisely because it hardened under water. Where gravity gave out, cathedral-scale pumping stations lifted the flow: Abbey Mills in the East End, so ornate it was nicknamed a cathedral of sewage, and Crossness on the southern marshes, opened in 1865 with the Prince of Wales in attendance, its great beam engines wrapped in painted ironwork.
The project also redrew the map of London. To carry the low-level sewer along the river, Bazalgette embanked the Thames itself: the Victoria, Albert and Chelsea Embankments reclaimed acres of foreshore, narrowed and quickened the river, and bundled the sewer together with an underground railway and public gardens in one of the great feats of multi-purpose engineering.
The detail that engineers still quote came at the drawing board. Having calculated the densest population his sewers might ever serve and the flow it would produce, Bazalgette doubled the pipe diameters, reasoning — as his remark is recorded — that "we're only going to do this once and there's always the unforeseen". That single act of deliberate over-building is much of the reason the system still serves a city of millions, more than a century and a half later, only lately reinforced by the Thames Tideway super-sewer.
The vindication was swift and grimly tidy. When cholera returned in 1866, it confined itself almost entirely to a district in the East End that Bazalgette's network had not yet reached — as clear a controlled experiment as epidemiology ever gets, and London's last major cholera epidemic. The sewers had been commissioned to abolish a smell, on the strength of a mistaken theory of disease, and they ended a plague. Bazalgette was knighted in 1875, and his modest memorial stands on the Victoria Embankment he built. Most Londoners pass it without a glance, which is fitting: his masterpiece has always done its work out of sight, and it has saved more lives than almost anything else his century built.
Quiz nuggets
- The Great Stink of June 1858 drove Parliament to pass the funding bill for London's new sewers in just eighteen days.
- Joseph Bazalgette, chief engineer of the Metropolitan Board of Works, built 82 miles of intercepting sewers fed by about 1,100 miles of street sewers, using some 318 million bricks.
- Crossness pumping station opened in 1865 with the Prince of Wales present; its ornate twin, Abbey Mills, was nicknamed a cathedral of sewage.
- Bazalgette doubled the calculated pipe diameters, remarking "we're only going to do this once and there's always the unforeseen".
- The 1866 cholera outbreak struck an East End district not yet connected to the new sewers — London's last major cholera epidemic; Bazalgette was knighted in 1875.