South London Memories: Marc and Isambard Brunel’s Thames Tunnel, an act of heroic engineering

Crossrail now looks unlikely to be completed for another year, but digging under London and the Thames has always been dangerous – and constructing the first tunnel killed more than 100 men.

Historian Stephen Halliday’s new book, Journey to Crossrail, looks at the troublesome and perilous effort to get commuters across London more quickly. Here we print an extract about Marc and Isambard Brunel’s Thames Tunnel, the first passenger route under the river, which is still part of the East London line south to New Cross – truly an act of heroic railway engineering.

Attempts to improve London’s transport had focused on River Thames crossings.

Four toll bridges were built across the river at Vauxhall, Waterloo, Southwark and Hammersmith, and in 1843 one of the most extraordinary engineering achievements of the century was completed.

This was the Thames Tunnel between Wapping and Rotherhithe, which was built using a tunnelling shield invented by Sir Marc Brunel (1769–1849), the less well-known but equally gifted father of Isambard Kingdom Brunel (1806–59), who supervised the work as resident engineer.

There is no doubt that the son inherited the father’s imagination and his engineering expertise.Born in France, Marc fled the French Revolution and in 1793 became the official engineer to the city of New York. In 1799 he came to England and invented a process for the mechanisation of the production of ships’ blocks, which guided the ropes of the Royal Navy’s sailing ships.

It was adopted by the Admiralty and, after much prevarication by the admirals, Marc was paid £5,000 for the process, which enabled him to be released from a debtors’ gaol.

He invented a typewriter, a knitting machine and a boot-making machine and built the floating docks at Liverpool.

But his greatest and most enduring achievement was the Thames Tunnel, built by his tunnelling shield, which he was inspired to build by observing the operations of the Teredo navalis, a mollusc known as a shipworm, which tunnelled into the wood of warships, its excrement hardening into a solid lining behind it and preventing the collapse of the tunnel.

The shield was a rectangular frame divided into three levels, or floors. On each level were cells, each large enough to accommodate a man with a pick and shovel. The men, known as ‘miners’, hacked away at the surface before them, protected by the frame from falling debris.

When each of the men had cleared about 6in the shield was forced forwards by screw jacks and the mining began again.

A conveyor belt removed the debris and bricklayers, following the miners, lined the space they had excavated. The tunnel, almost 400m long, took 18 years to complete.

Progress was interrupted by mishaps, including equipment failures, bankruptcy, inundations (one of which nearly drowned Isambard Brunel) and accidents to the miners whose hazardous work in insanitary conditions made them vulnerable to illness as well as injury.

More than 100 of them died. At one particularly delicate point during the operation, following the collapse of the tunnel, Isambard, fresh from escaping drowning, was lowered into the river seated in a diving bell (accompanied by his redoubtable mother, Sophia) to examine the damage.

The water was kept beneath them by the pressure of the air in the bell. He located the breach in the tunnel roof and arranged for it to be sealed with sacks of clay.

This operation was repeated several times. Some of the water was then pumped from the tunnel, which he entered on a punt, proceeding to a point close to where the shield was to be found.

He then crawled across a bank of slime to the shield itself and, by candlelight, ascertained that it could be repaired.

In 1841 Marc was knighted by Queen Victoria at the suggestion of her husband, Prince Albert, who was impressed by the enterprise shown by the engineer and thought it would encourage him in the final stages of the long and challenging project.

The tunnel entered service as a foot tunnel on March 25, 1843 amidst much rejoicing. The cheering crowds observed a policeman wearing a medal that signified he had fought at Waterloo, leading the long procession through the tunnel to the strains of Handel’s See the Conquering Hero Comes.

Four months later, in July 1843, an even grander scene saw Queen Victoria visit the Thames Tunnel.

On that occasion, recorded by the Illustrated London News, a gallant stallholder selling silken goods in the tunnel emulated Sir Walter Raleigh and ‘displayed his loyalty in a peculiar manner. All the silk handkerchiefs disposed on his stall for sale were removed and placed on the ground for Her Majesty to pass over.’

They were then presumably sold to loyal subjects at an enhanced price. Such was the novelty of the tunnel that one million people visited it in the three months which followed its opening – more than half the population of London at the time.

Nevertheless, the tunnel was never profitable as a foot tunnel, and in 1865 it was bought by the East London Railway to carry its trains beneath the river, as it still does. It is one of the more neglected corners of the London Underground network, but it runs through the world’s oldest tunnel beneath a river.

Moreover Brunel’s tunnelling shield, which made its construction possible, is the ancestor of the shields which later built London’s deep-level tubes, beginning with the City & South London Railway in 1890 (now the Northern line) and, of course, the Channel Tunnel and Crossrail.

Journey to Crossrail by Stephen Halliday is published by the History Press, price £14.99.