Thames Tunnel (1843): The Brunels' Tunnel Under a Tidal River

The Thames Tunnel is a brick tunnel under the River Thames in London, running between Rotherhithe on the south bank and Wapping on the north. It opened to the public on 25 March 1843 after almost eighteen years of dangerous work, and it is the first tunnel known to have been built successfully beneath a navigable river. Designed by Marc Isambard Brunel with the help of his son Isambard Kingdom Brunel, it introduced the tunnelling shield and still carries trains today.

Background: crossing a crowded river

In the early nineteenth century the Pool of London was one of the busiest stretches of water in the world. Bridges downstream of London Bridge would have blocked tall ships, so a tunnel seemed the best way to link the docks on either bank for carts and people.

Earlier attempts had failed. Between 1807 and 1808 a team of Cornish miners driving a small pilot tunnel between Rotherhithe and Limehouse was repeatedly flooded, and the scheme was abandoned. Many engineers concluded that tunnelling through the soft, waterlogged ground under the Thames was impossible.

Marc Brunel’s tunnelling shield

Marc Isambard Brunel, a French-born engineer who had settled in England, approached the problem differently. In 1818 he and Thomas Cochrane patented a tunnelling shield. According to a well-known account, he was inspired by the shipworm, a mollusc that bores through ship timbers while protecting itself with its shell.

The shield used for the Thames Tunnel was a large iron framework divided into 36 cells in three tiers. In each cell a miner removed the earth in front of him a few inches at a time, behind a set of boards. The whole frame was then pushed forward by screw jacks, and bricklayers immediately lined the exposed ground behind it. The shield supported the face and roof while the permanent brick lining was built.

Construction, floods and deaths

The Thames Tunnel Company was formed in 1824. Work began in 1825 by sinking a large brick shaft at Rotherhithe, and the shield began advancing under the river later that year. In 1826 Isambard Kingdom Brunel, then about twenty, became resident engineer.

Conditions were terrible. The river above was heavily polluted with sewage, and water, gas and mud seeped into the workings. Men suffered from illness, and Marc Brunel himself fell seriously ill. The river broke in on 18 May 1827, flooding the tunnel. Isambard went down in a diving bell to inspect the hole in the riverbed, which was plugged with bags of clay before the tunnel was pumped out. In November 1827 a banquet was held in the tunnel to restore public confidence.

On 12 January 1828 a second, worse flood struck. Six men drowned, and Isambard was swept along by the water and seriously injured. With money exhausted, the tunnel face was bricked up and work stopped for about seven years.

Completion and opening

A Treasury loan allowed work to restart in 1835 with a new, improved shield. Progress remained slow and further inundations occurred, but the tunnel reached Wapping in 1841. Marc Brunel was knighted in the same year.

The tunnel opened on 25 March 1843. It is about 396 metres (1,300 feet) long and consists of two arched passages side by side. Ramps for carriages were never built because money ran out, so it served only pedestrians, who paid a penny to pass through. It drew large crowds and became a celebrated sight, with stalls and entertainments in its arches, but it never earned enough to repay its costs and later gained a poor reputation.

Key people

• Marc Isambard Brunel (1769–1849): French-born engineer who designed the shield and the tunnel and directed the work for nearly two decades.
• Isambard Kingdom Brunel (1806–1859): his son, resident engineer from 1826 until his injury in 1828, later famous for railways, bridges and ships.
• Thomas Cochrane (1775–1860): naval officer who shared the 1818 shield patent with Marc Brunel.
• The miners and bricklayers: the workforce who dug the face cell by cell, often in foul air and constant danger.

Railway use

In 1865 the tunnel was bought by the East London Railway Company, and trains began running through it in December 1869. It later became part of the London Underground’s East London line and, since 2010, the London Overground. In the nineteenth century its success with a shield encouraged later tunnels, including the cast-iron lined Tower Subway, opened in 1870, and the deep-level tubes that followed the Metropolitan Railway.

Timeline

• 1818: Marc Brunel and Thomas Cochrane patent the tunnelling shield.
• 1825: Work begins at Rotherhithe; the shield starts advancing under the river.
• 1827, 18 May: The river breaks into the tunnel for the first time.
• 1828, 12 January: A second flood kills six men and injures Isambard Kingdom Brunel; work is suspended.
• 1835: Work resumes with a new shield after a government loan.
• 1843, 25 March: The tunnel opens to pedestrians.
• 1869, December: The first trains run through the tunnel.

Why it matters

The Thames Tunnel proved that a large tunnel could be driven through soft, wet ground beneath a busy river. The shield method it pioneered underlies modern tunnelling, from the London Tube to the Channel Tunnel. It also launched the career of Isambard Kingdom Brunel, whose SS Great Britain was floated out the same year.