21 tributaries flow directly into the Thames within the spread of Greater London. Most are now virtually invisible.
The Walbrook once flowed openly through the centre of Roman London, but it began being paved over in the 1460s, and it was completely covered by 1562. Archaeologists have discovered scores of human skulls in the bed of the river which are thought to be the heads of Romans executed by Boudicca’s rebelling army. The Walbrook now runs directly under the Bank of England’s vaults.
The Fleet was an open sewer for centuries. In 1728 Alexander Pope wrote in his Dunciad, ‘To where Fleet-ditch with disemboguing streams / Rolls the large tribute of dead dogs to Thames/The king of dykes! than whom no sluice of mud/with deeper sable blots the silver flood’. Now it is a fully incorporated part of the London sewage system built by Joseph Bazalgette in the 1860s.
Although the Tyburn is also now no more than a sewer, Grays Antique Centre near the junction of Oxford St and Davies St has an open stretch of flowing water in its basement which is a tributary of the Tyburn. The water is clear here, but by the time it passes underneath Buckingham Palace, it is as black as molasses.
The Westborne is now known as the Ranelagh Sewer. Its subterranean gurgles have led some Chelsea homeowners to think their cellar is haunted. It can still be seen at Sloane Square Tube Station, where it crosses the track in a huge metal pipe.
Other hidden rivers of London include: the Ching, Moselle, Quaggy, Silk Stream and Neckinger.
Many rivers could once be seen flowing into the Thames in London, but as its population grew and commerce developed in the Middle Ages, many of these rivers became little more than open sewers.
Bit by bit, they had to be paved over to contain the pollution and make room for new buildings. But still the filthy water was the cause of many epidemics of diseases such as cholera.
One warm summer in 1858, the stench of these foul rivers was so bad that it filled the chamber of the House of Commons. This finally persuaded the government to vote for engineer Joseph Bazalgette’s project to build a vast network of brick-walled sewers.
This engineering marvel incorporated and redirected many of London’s subterranean rivers.
Men who earned a living by searching London's sewers for lost valuables were known as 'toshers'.
Fleet Street is named after the Fleet River, which From the 13th century until Victorian times was an open sewer, flowing with excrement.
In the late19th century, a coffin was spotted floating in the Thames. It seemed to have come all the way from West Norwood Cemetery, yet the grave itself was found to be undisturbed.
Investigations revealed that the grave had been dug too close to the course of the Effra, which runs beneath the cemetery. The coffin had been washed into the river and floated for miles underneath South London, all the way to the Thames at Vauxhall.
Joseph Bazalgette, who built London's sewers system, is the great-great-grandfather of Peter Bazalgette, the man behind Big Brother.