The terrible smell from the River Thames had made the new Houses of Parliament almost uninhabitable. In a desperate attempt to keep it out, the curtains had been soaked in chloride of limeA chemical often used for bleaching. . According to The Times, MPsMembers of Parliament. MPs are elected to represent people in 650 different geographical areas.  who ventured into the library "were instantaneously driven to retreat, each man with a handkerchief to his nose".

The smell came to be known as "the great stink". Sewage had been building up in the river for centuries; the summer of 1858 brought a heatwave which caused it to ferment. The result was what Benjamin DisraeliA 19th-Century politician who was Britain's first and only prime minister of Jewish origin. called "a StygianExtremely dark and gloomy. Relating to the river Styx, the river of the underwood. pool reeking with ineffableSomething that cannot be expressed in words. and unbearable horror".¹

Along with the smell came disease. Over the previous 25 years, cholera outbreaks had claimed over 30,000 lives.² A grim cartoon in PunchAlso known as The London Charivari, a British satire magazine published between 1841 and 1992. showed a skeleton rowing up the Thames.  

The horrific pong impelled MPs to pass a new law in record time. The Metropolitan Board of Works was given a huge £3m budget to construct a new sewage system.

Under its chief engineer, Joseph Bazalgette, 82 miles of new sewers were built, some of them bigger than the tunnels for the Underground. The Observer called it the "most extensive and wonderful work of modern times." The great stink was over, and the threat from cholera receded.

Today London still depends on Bazalgette's system, even though its population has trebled.³ Extreme rainfall caused by climate change has strained it further. Now river pollution is raising new fears for public health. Before March's Oxford and Cambridge Boat Race, the rowers were warned to take extra care because of high levels of E. coliEscherichia coli is a large group of bacteria. Many are harmless, but some can cause sickness. in the water.

The problem is not confined to the capital. This week, the BBCThe British Broadcasting Corporation is the UK's national broadcaster. revealed that millions of litres of raw sewage were pumped illegally into Lake Windermere in the Lake DistrictA mountainous area of northwest England. It contains the country's largest natural lake, Windermere. in February. United Utilities failed to report the incident for 13 hours. Previous sewage discharges into the lake have caused it to turn green and maybe even toxic, as phosphorus builds up and algae blooms.

According to the Environment Agency, only 16% of surface waters in England achieved good ecological status in 2023. For Northern Ireland the figure was 31%, for Wales 40% and for Scotland 61%.

In England, raw sewage was released into rivers and seas for over 3.6 million hours over the past year - more than double the figure for the previous 12 months.⁴ The worst rivers affected were the Irwell and its tributary the Croal, which flows through Greater Manchester.

Water companies are allowed to make such releases in extreme weather conditions to stop sewers being overwhelmed. They say the increased figures are down to heavier rainfall.

But campaigners say that many releases are happening illegally because sewage works are not operating properly. They claim that water companies have not spent enough money on maintaining the system.

Thames Water has faced huge criticism for paying hundreds of millions of pounds to shareholders which could have been invested in infrastructureThe basic systems and services that a country needs to keep it going., and then threatening customers with higher bills to pay for it. But Scottish Water, which is publicly owned, has also been responsible for a huge number of sewage spills.

In April last year, the government announced a new plan to improve water quality. It included unlimited fines for companies which broke the rules on dumping sewage.

Is this a new great stink?

Yes: The amount of sewage being discharged into rivers and the sea is appalling. The improvements needed to the infrastructure will involve years of building work and cost billions of pounds.

No: Sewage treatment plants are becoming more sophisticated all the time. Much of the Victorian infrastructure still works extremely well - it just needs its capacity to be increased. 

Or... The situation would be better if it were the great stink - then politicians would have to take urgent action. Because a lot of people never think about rivers, it is not considered a pressing issue.

Chloride of lime - A chemical often used for bleaching.

MPs - Members of Parliament. MPs are elected to represent people in 650 different geographical areas. 

Benjamin Disraeli - A 19th-Century politician who was Britain's first and only prime minister of Jewish origin.

Stygian - Extremely dark and gloomy. Relating to the river Styx, the river of the underwood.

Ineffable - Something that cannot be expressed in words.

Punch - Also known as The London Charivari, a British satire magazine published between 1841 and 1992.

E. coli - Escherichia coli is a large group of bacteria. Many are harmless, but some can cause sickness.

BBC - The British Broadcasting Corporation is the UK's national broadcaster.

Lake District - A mountainous area of northwest England. It contains the country's largest natural lake, Windermere.

Infrastructure - The basic systems and services that a country needs to keep it going.