In the nineteenth century, the Port of London was at its height and ships had to queue for berths. As well as the problem of delays, there was another difficulty: if the ship moored south of the river and its cargo was destined for the north bank, or vice versa, it all had to be transported slowly overground along the riverside, across hectic London Bridge and back down the opposite bank. The solution proposed: a tunnel allowing horses and carts to quickly pass from one side of the river to the other.
Brunel’s tunnel was an engineering marvel, the first to be built under a navigable river. It required the invention of a new tunnelling technique: the tunnel shield, which provides support as each new section is built. (Previous tunnels tended to be ‘cut and cover’, where a big trench was dug and then roofed over – the unsuitability of this for tunnelling under a river is obvious!). Even with such revolutionary techniques, the tunnel took 18 years to build and was only completed in 1843.
However, as is often the way with such grandiose projects (think Millennium Dome), things went rather wrong. Money ran out, and although there were stairs down to the tunnel, the ramps for horses were never built. Instead the tunnel became a pedestrian attraction. There were under-river banquets, a shopping arcade, and even fairs. Souvenirs were sold, some of which can be seen at the fascinating Brunel Museum by the tunnel’s Rotherhithe entrance. However, over time it came to attract dodgy characters and declined in popularity.
Eventually, in 1869, the tunnel became part of the new East London Railway and was closed to pedestrians. The tunnel will continue to be an important part of London’s transport network when it reopens as part of the extended line (ironically named the Overground) next year: not bad for a pioneering tunnel well over 150 years old!