Thames Tunnel

FACTSFact sheet

01A river that would not take a bridge

At the turn of the nineteenth century, the traffic of the Port of London was moving down the Thames beyond London Bridge, toward the new docks. Anyone who needed to cross from one bank to the other along that stretch took a boat. A low bridge would block the tall ships coming up the river; a high bridge, with the technology of the day, was not feasible. That left going underneath.

Others had tried. In 1798–1799, Ralph Dodd wanted to drive a tunnel further downriver, between Gravesend and Tilbury, and gave up. Between 1805 and 1808, the Thames Archway Company brought in Cornish miners, with the engineer Richard Trevithick, to dig a narrow heading precisely between Rotherhithe and Wapping. They got to about 1,000 of the planned 1,200 feet before the water came in. The conclusion of many engineers was that the bed of the Thames, of mud and loose sand, could not be dug through.

02The worm and the cage

Marc Isambard Brunel, an engineer born in France in 1769, told how he got the idea. In a letter to his granddaughter, from March 1842, now held in the archive of Royal Museums Greenwich, he recalls that around 1812, while working at the Chatham dockyard, he saw a piece of condemned ship's timber bored through by the shipworm, the mollusk that eats away at hulls. If those creatures could make small protected tunnels, he wrote, men could too, with equivalent protection. It is Brunel's own account, given thirty years later; the Brunel Museum treats it as the version usually told.

In January 1818 he patented a method for driving tunnels underground. The centerpiece was the shield: twelve iron frames set side by side, each divided into three tiers, for a total of 36 cells. In each cell, a miner removed a few inches of earth behind boards that held up the face, one board at a time. When they had all advanced, the frame was pushed forward by jacks bearing on the finished lining, and the bricklayers laid brick right behind it. The ground was never left unsupported for more than a few hand-spans. The work would be divided into two parallel arched galleries, linked by openings, in a block of brick and Roman cement.

03Beneath London's sewage

The Thames Tunnel Company, with investors such as the Duke of Wellington, won authorization from Parliament in June 1824. In March 1825 work began at Rotherhithe, on the south bank, on the entrance shaft: a brick cylinder 50 feet across, built on an iron ring at the surface and sunk little by little as the earth was dug out from inside. At the end of that year the shield began to advance horizontally, heading north.

Progress was a few feet a day, when there was progress at all. River water, which carried London's sewage, leaked in through the working face; the air was foul, and methane coming out of the mud caught fire in the lamps. Workers fell sick with dizziness, pains and infections. Isambard Kingdom Brunel, Marc's son, took over the running of the site in practice in 1826 and was confirmed as resident engineer in 1827.

In May 1827, with 549 feet dug, the riverbed gave way and the river poured in. To plug the hole, Isambard went down in a diving bell and had bags of clay dropped onto the riverbed. The tunnel was pumped out and, in November of that year, the company held a banquet inside it, organized by him.

04The morning of 12 January 1828

Shortly before six in the morning on 12 January 1828, the face of the tunnel gave way again. Six men died: Thomas Ball, J. Long, Thomas Collins, Jeptha Cook, who left six children, George Evans and a newly hired man named Lincoln. Isambard, who was at the working face, was swept by the water to the Rotherhithe shaft, pulled out unconscious and revived. With serious internal injuries, he spent months recovering, first in Brighton and then in Clifton, near Bristol.

The money ran out before the repairs, and in August 1828 the face of the tunnel was sealed with a brick wall. The work that was supposed to prove one could dig under a river became, for years, a walled-up passage beneath the Thames.

05The government pays for the rest

The restart came with public money. In December 1834 the first installment arrived of a Treasury loan, of £270,000 according to the Transport for London archive, or part of £247,000 raised, according to other sources. The old shield, worn and warped, was dismantled in 1835, and a new, sturdier one went to work in March 1836. The stoppage lasted six, seven or eight years, depending on which date is taken as the restart.

The river kept coming in: there were floods in August and November 1837, in March 1838 and in April 1840. According to a survey based on the biography written by L. T. C. Rolt, the flood of November 1837 killed one more miner. There is also a record of an engineer who died of a fever blamed on the tunnel water. How many died in all over the eighteen years of work, no source consulted adds up. In 1839 the shield reached the Wapping bank, Marc Brunel was knighted in 1841, and the excavation reached the north shaft in November 1841.

06The penny attraction

The tunnel opened to the public on 25 March 1843, with a ceremony and a procession. It cost £634,000 including the fitting-out. The spiral ramps that were to bring carts down to the bottom were never built for lack of money, and the freight passage became a pedestrian passage, via long stairways inside the shafts, at 1 penny per person. In the first 24 hours, 10,000 people paid to get in, according to the TfL archive; other sources speak of 50,000. Within a few months it passed a million visitors, and Queen Victoria visited it in July 1843. The archways between the galleries filled with souvenir stalls, and there was a yearly fair with musicians and tightrope walkers.

The novelty wore off. By the late 1850s the tunnel had a reputation as a seedy place. In 1865 the newly formed East London Railway bought it, for £200,000 according to TfL, and on 7 December 1869 the first train ran through. Marc Brunel died in 1849, and Isambard ten years later.

07A tunnel that still carries trains

Brunel's tunnel has never gone out of use. It was electrified in 1913, absorbed into the London Underground in 1933, closed for refurbishment in 1995, when a proposal to cover the brick with sprayed concrete caused protests and led to its listing, and reopened in 1998. Since 2010 it has been part of London Overground, and since November 2024 it has been the under-river section of the Windrush line. The idea of the shield moved on: from 1869, Peter W. Barlow and James Henry Greathead redesigned it as a cylinder, the design from which today's tunnel boring machines descend, at a distance.

The Rotherhithe shaft and the drainage pump house form the Brunel Museum. The museum had £2.1 million from the National Lottery Heritage Fund to restore the two buildings and build an entrance pavilion in time for the 200 years since the start of the work. Studies of the Windrush line tunnel, just below, delayed everything, TfL raised objections to the pavilion's site, and in December 2025 the fund decided not to go ahead with the works. Two hundred years after Brunel, disturbing the ground above that tunnel is still an engineering problem. In September 2026, the museum's collection on the tunnel received Designated Status from Arts Council England, reserved for collections of outstanding importance.

MYTHSWhat people say and what the record shows

• What people say

  It was the first tunnel ever built under a river.

  What the record shows

  The sources put it more carefully: the first known to have been successfully completed under a navigable river. The 1805–1808 attempt, at the same spot, got to about 1,000 feet before flooding, and there is an ancient account, of uncertain proof, of a tunnel under the Euphrates, in Babylon.

• What people say

  Brunel's shield is the basis of every modern subway.

  What the record shows

  The concept, a protective shell that advances while the lining is built just behind it, is the basis of tunneling today, as the TfL archive notes. But Brunel's shield was rectangular; today's machines descend from the cylindrical shield of Barlow and Greathead, used from 1869.

• What people say

  Brunel invented the shield after watching a worm.

  What the record shows

  That is Brunel's own version, in an 1842 letter about something he said he saw around 1812 at the Chatham dockyard. The shipworm, by the way, is a mollusk, not a worm. The Brunel Museum presents the story as the one usually told.

• What people say

  The tunnel was built for carriages.

  What the record shows

  It was designed for freight carts, but the spiral access ramps were never built for lack of money. From 1843 to 1869, it was a pedestrian passage, with stairways in the shafts and a toll of 1 penny.

QUESTIONSFrequently asked questions

Next episode · Structure 21 · premieres Feb 25, 2027

Eads Bridge

Mississippi River, between St. Louis, Missouri, and East St. Louis, Illinois, United States · 1867–1874

Resting on bedrock, beneath some 25 meters of sand that the Mississippi kept shifting, three arches of more than 150 meters each made of a metal that had never been the main one in a large structure, with no falsework in the river and without stopping the steamboats.

Read the story →

SOURCESSources

1. TfL Corporate Archives, Research Guide No 25: The Thames Tunnel, 2024 — content.tfl.gov.uk
2. Historic England, Thames Tunnel, list entry 1242119 (Grade II*), 1995 — historicengland.org.uk
3. American Society of Civil Engineers, "Thames Tunnel", International Historic Civil Engineering Landmark — asce.org
4. London Museum, "The Thames Tunnel: Marc Brunel's engineering marvel" — londonmuseum.org.uk
5. Royal Museums Greenwich, "Musing on a mollusc: Brunel's inspiration for the Thames Tunnel" (letter from Marc Brunel, 10 March 1842) — rmg.co.uk
6. Brunel Museum, "1828 Tunnel Flood" — thebrunelmuseum.com
7. Brunel Museum, "Tunnel Shaft" — thebrunelmuseum.com
8. Brunel Museum, "Working at the Face – Inspiration" — thebrunelmuseum.com
9. Brunel Museum, "New Insights into the Thames Tunnel Designs" — thebrunelmuseum.com
10. Brunel Museum, news from 2026 — thebrunelmuseum.com
11. Linda Hall Library, "Scientist of the Day: Marc Isambard Brunel" — lindahall.org
12. National Transport Trust, "Thames Tunnel" — nationaltransporttrust.org.uk
13. Guinness World Records, "First tunnel under a navigable waterway" — guinnessworldrecords.com
14. PBS, Building Big, "Thames Tunnel" — pbs.org
15. Mark Cartwright, "Thames Tunnel", World History Encyclopedia, 2023 — worldhistory.org
16. Andie Byrnes, "Marc Brunel in Rotherhithe: the construction of the Thames Tunnel 1825–1843", A Rotherhithe Blog, 2015 — russiadock.blogspot.com
17. ianVisits, "Brunel Museum's expansion put on hold after railway tunnel complications", 29 May 2026 — ianvisits.co.uk
18. Tom de Castella, "Tate + Co's expansion of Brunel Museum runs out of steam", Architects' Journal, 14 July 2026 — architectsjournal.co.uk
19. Evie Flynn, "Rotherhithe museum for first underwater tunnel gains Designated Status", Southwark News, 17 September 2026 — southwarknews.co.uk
20. Wikipedia, "Thames Tunnel" and "Tunnelling shield" (starting point) — en.wikipedia.org

Images

• Fig. 01 — The tunnel as a pedestrian attraction, in an engraving published in Germany in 1839, four years before the opening: Bibliographisches Institut, Hildburghausen (Meyer's Universum, vol. 6) · Public domain
• Fig. 02 — The shield seen from the front, with its 36 cells in three tiers, in a popular English magazine from November 1832: Autor não identificado (The Penny Magazine) · Public domain
• Fig. 03 — Visitors in one of the galleries, in a nineteenth-century lithograph that gives the tunnel a length of 1,300 feet, a width of 38 and a height of 22: Autor não identificado (Library of Congress, Popular Graphic Arts) · Public domain
• Fig. 04 — The northbound train gallery in 2007, already a railway tunnel, with Brunel's original arches on the left: Steve McSherry · CC BY-SA 3.0
• Fig. 05 — The two galleries, side by side, on a walking tour with the line closed, in May 2014: Martyn Pattison · CC BY-SA 2.0
• Fig. 06 — The Rotherhithe entrance shaft, begun in 1825, now part of the Brunel Museum, with the staircase installed in 2016: Z22 · CC BY-SA 4.0