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Marc Isambard Brunel: The London Underground

Marc Isambard Brunel

French-born engineer, Marc Isambard Brunel, was the man behind the Thames Tunnel – described as the “eighth wonder of the world” when it opened in the 19th century, because it allowed people to walk under water.

Today, it’s part of the London Underground system, but when it opened, the Thames Tunnel was the capital’s biggest tourist attraction. On 25th March 1843, around 50,000 people paid one penny each to descend the staircase and walk through the passage underneath the River Thames for the very first time.

Within three months, visitors were coming from far and wide and an estimated one million people had visited the pedestrian tunnel. In an era when people travelled by boat or horse-drawn carriage, it was amazing that so many people made their way to London to see a visitor attraction.

Wealthy tourists from all over the world arrived and local people made the most of the influx of visitors, selling souvenirs and providing entertainment in the tunnel’s arches.

The Thames Tunnel was Brunel’s masterpiece and its success was even sweeter because it had been the most challenging engineering project he had ever tackled. It was beset with problems, so the fact it had opened at all was a tribute to the engineer’s skills.

Famous family

The name “Isambard Brunel” will be familiar to most British people, but probably because of Marc’s more famous son, Isambard Kingdom Brunel, who designed and built many famous structures in the 19th century, such as the Royal Albert Bridge across the 1,100ft-wide River Tamar in Cornwall.

Marc Isambard Brunel’s most famous feat of engineering, the Thames Tunnel, was equally important to the development of England’s transport system. He was also responsible for introducing new safety measures for the labourers who were tunnelling underground.

He invented the “tunnelling shield”, also known as the “miners’ cage” (a solid structure that enabled miners to dig inside its protective frame), with bricklayers building the wall as they moved forward. This removed the risk of the tunnel collapsing and trapping the workers under the rubble.

Early career

Brunel led a colourful and interesting life. Born in Hacqueville, Normandy, on 25th April 1769, into a wealthy farming family, his father, Jean Charles Brunel, expected Marc (he second son) to follow the family tradition. The first son would inherit the family farm and the second son would enter the priesthood.

However, he had no interest in Greek, Latin, or any other aspect of the classical education required. Instead, he was excellent at mathematics and drawing. He didn’t want to become a priest, so instead, his father sent him to become a naval cadet on a French frigate.

His ship visited the West Indies but while overseas, the French Revolution broke out in May 1789, when Brunel was 20, so the crew was paid off. He returned to live with his family, but as a Royalist sympathiser, he couldn’t stay in France.

Reluctantly, he left for New York, leaving behind a young English governess he had met in Rouen, called Sophia Kingdom.

Arrival in Britain

Brunel worked in the United States during the 1790s, being appointed Chief Engineer of New York in 1796, after first being involved in a project to link Lake Champlain with the Hudson River by canal.

He set sail for England in February 1799, after learning that the Royal Navy was having difficulties in obtaining 100,000 hand-made pulley blocks to kit out its fleet of ships. He designed a machine that would automate their production and on 7th March, he arrived at Falmouth to put his plans into action.

Miss Kingdom had fled the French Revolution and returned to safety in England, after she was mistakenly accused of being a spy. She and Brunel met up again and were married on 1st November 1799. They had two daughters, Sophie and Emma, followed by their son, Isambard Kingdom, in 1806.

Thames Tunnel

The Thames Archway Company had been founded in 1805 with the aim of building a tunnel under the Thames between Limehouse and Rotherhithe. British inventor and mining engineer, Richard Trevithick, was commissioned by the company to carry out the construction work.

He engaged Cornish miners to dig the tunnel, but in 1807, conditions became treacherous and they hit quicksand, after completing more than 1,000ft. It was considered too dangerous to continue and the project was all but abandoned.

Brunel had drawn up plans for a similar scheme under the River Neva in Russia, but it was never given the green light. He had patented his cast iron tunnelling shield in 1818 as a safety device to enable safe digging underground.

So sure was he that his system would enable safe digging of the Thames Tunnel, that he wrote to every influential person to ask if it could go ahead. In February 1824, his perseverance paid off, as a meeting was held for interested parties. They backed his invention and purchased 2,128 shares, costing £50 each. His device was produced by Henry Maudslay’s company in Lambeth.

The Thames Tunnel Company received royal assent in June 1824 and the tunnel was finally allowed to proceed. It was aimed at providing a thoroughfare for horse-drawn traffic and to move cargo. Every day, the trade of the world travelled along the Thames: there could be as many as 3,000 tall ships on the river, so a new trade route was needed but somewhere along the line, the tunnel became more of a tourist attraction.


In February 1825, construction began with a vertical shaft being dug on the Rotherhithe bank, 150 feet back from the water’s edge. A 50ft-wide iron ring was first constructed above the ground and a brick wall 40ft tall and 3ft wide was built on top, using excavation pumps powered by a mighty steam engine.

Brunel’s workers removed the soil beneath the ring, using his safety tunnel. This was done to deliberately make the whole shaft sink under its own weight. An extra 50,000 bricks were added until it had sunk to the correct depth. The Rotherhithe shaft was in place by November 1825, so the construction of the tunnel could begin in earnest.

Made up of 12 frames that stood side by side, each moving forward independently, the tunnelling shield was the reason the Thames Tunnel could be built. Maudslay had also provided steam-powered pumps for the project.

One frame accommodated 36 miners. Once the digging had reached the required place, the safety frame would be moved forward using large jacks and put in place at the next section of the tunnel, where digging commenced again. As the safety shield progressed, the bricklayers were lining the walls behind it. In total, 7.5 million bricks were required.

It wasn’t a pleasant job for the construction workers, who were reportedly flooded with raw sewage from time to time. They also had to dodge flames caused by the ignited methane gas. Described as the “worst job in the world”, it was so exhausting the men could work only a four-hour shift before being replaced by a new batch of workers. If they worked any longer, they would pass out.

It was reported there was a flood in the tunnel while Brunel himself was underground and he had to flee for his life, while sadly, six other men drowned.


Work was slow, and the tunnel grew at only 12 feet per week. The company directors started worrying about the costs. It had cost £454,000 to dig the tunnel and an additional £180,000 to fit it out, exceeding the initial estimate.

Company chairman, William Smith, wanted to replace Brunel as the engineer and scrap his safety shield, claiming the digging should be completed more cheaply, using traditional methods, but Brunel stood his ground and weathered the storm, seeing the project through to completion, eventually being helped by his 18-year-old son, Isambard Kingdom.

Charging a shilling per person, the company directors invited visitors to watch the digging in operation, especially the mighty shield. Around 800 visitors went to watch each day – an amazing number, considering the smell from the sewage and methane gas must have been phenomenal!

Grand opening

The tunnel opened in 1843, but initially just for pedestrians, as the company had run out of money and was unable to build the cargo ramps. However, it became a massive visitor attraction right away and soon earned its title of the eighth wonder of the world!

In 1865, the East London Railway Company purchased the tunnel and work then began to dig new tunnels to link the Thames Tunnel to Great Britain’s rail network. In 1869, trains finally began running through the tunnel and for the first time, it fulfilled its intended purpose.

In 1913, the line was electrified and became part of the London Underground – the East London Line. Today, the Thames Tunnel is the oldest in the underground network and the London Underground is the oldest underground system in the world.

LH-PLC is keeping the UK’s rail systems on track by providing railway air conditioning services using the latest state-of-the-art facilities. Please contact us for further information.

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