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09 August 2010 | By: Londonist

The Fleet River: Paddling Through London's Most Famous Sewer

The Fleet River: Paddling Through London's Most Famous Sewer

We're in the City of London, splashing about in the river. But this is not the Thames. Along its 'banks' are iron hoops for securing boats, yet no vessel has passed this way in centuries. It is an ancient river, fished by the Romans and the Britons who preceded them. It still flows from Hampstead Heath, through Kentish Town and Camden Town, round the curve of King's Cross, over Holborn and then on toward the Thames. A million people cross the river every day without ever knowing. This is the Fleet, the largest of London's 'vanished' rivers. And we're enjoying a rare opportunity to paddle along its slimy bed thanks to an invitation from the good people at Thames Water, who now maintain the Fleet as part of London's sewer system.

Being a sewer, you'd never notice it was there. But an observant walker, passing along Farringdon Street or Road, would notice many signs of this former river, from the sloping side streets which once formed its banks, to the ancient place names such as Turnmill Street and Old Seacole Lane. Most noticeable of all is the magnificent Holborn Viaduct - a Victorian 'flyover' built to span the Fleet valley. It's here where we meet representatives of Thames Water who will take us down into this entombed and tainted watercourse.So how does one dress for an amble in excrement? As skimpily as possible, it turns out. The professionals, known colloquially as flushers, wear nought but undies beneath their protective suits - it can get pretty stuffy down beneath. Everyone must wear the full kit of protective gear: crotch-high waders, super-thick socks, a billowing paper suit to guard against random splashes, a hard hat, rubber gloves, a safety harness for ladder climbing and a portable oxygen cylinder in case of gas buildup.We aren't the only ones braving the torrent today. Dan Snow and a team from the BBC took the tour ahead of us to film for a new series on Medieval London. We're more than happy to take sloppy seconds, and follow 'Flusher-in-Chief' Rob Smith towards the manhole.A vertical ladder takes us down about five metres below ground into a narrow entrance gallery. This pebble-strewn corridor soon leads out into the sewer proper, flowing down toward the Thames at a fair whack thanks to the steep Hampsteadian gradients a couple of miles upstream. It's noisy and cramped and a little intimidating, but there is no strong smell and little in the way of detritus. Walking against the current is slow but relatively easy; the stream flows barely higher than ankle level as we progress Fleet (if not fleet) of foot. During storms, the level can reach almost to the ceiling, some three or four metres above us. At these times, the normal flow (into the Low Level Sewer at Embankment, and thence to Beckton for treatment) is insufficient and the Fleet overcomes a series of one-way valves to once more drain into the Thames.Rob takes us to a bifurcation point, somewhere beneath Holborn Viaduct. Here the main Fleet sewer divides in two (for reasons no one seems quite sure about, though this split is already clear on John Rocque's map of 1746) before comingling once more near Ludgate Circus. The parting of currents at this point made for treacherous footing, and we took extra care rounding the bend.We're now standing at the approximate place where Holborn bridge once carried horse-drawn traffic over the Fleet, linking High Holborn and Newgate. Here, Rob points out a rather special survival. A series of iron hoops are embedded at intervals along either wall as far as the torch-aided eye can see. The flushers believe that these hoops date from times when the Fleet was an open-air river, and were used for securing barges. This seems somewhat unlikely, given that this section of Fleet was largely covered over in 1737.Our visit lasts little more than 20 minutes. Emerging back onto Farringdon Street is the most surreal moment of all, clambering out of a slimy, pitch-dark hole into a busy high street.LinksOur previous trip into the much larger Northern Outfall Sewer.A photographic tour of the Fleet above ground by Diamond Geezer. Still the best account of the river's course on the web.Backlit photos of the Fleet by a group of drainers, illegally exploring its course.Our thanks to Thames Water for their hospitality (if that's the right word). Words by M@, Pictures by DeanN.

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Tim Newbury

Fascinating. It's very likely that the twin parallel culverts from Holborn Viaduct to Ludgate Circus were constructed in that manner in response to the proposed use of the newly reclaimed ground above. The split as you see it on John Rocque's map is actually the two rows of shops and stalls (aboveground) that formed Fleet market, as can be seen in this image.

I'd agree with you concerning the iron hoops, it's very unlikely that they are in any way related to mooring vessels. It's more likely that they are remnants of maintenance or construction access allowing people to work at a mid tunnel height above the water flow along that section.

Scott Wood

Any sinister, echoing oinks?


You are everywhere!


May I humbly and speculatively suggest that the iron hoops were for hanging chains from?
Although what the chains were for I couldn't say. Mooring boats too?! haha


Although they seem in such good nick I wonder if they were ever used at all, or only briefly - such as Tim Newbury suggests.