UK TUNNELLING: PAST, PRESENT AND FUTURE

This article relates the progress of tunnelling in the UK from the mid-19th century onwards. It describes its many innovations and achievements, examines present UK tunnelling activities, and assesses the medium- and long-term prospects for UK tunnellers at home and abroad. The tunnels built in the UK include sewer tunnels, water tunnels, tunnels for hydroelectric schemes, rail tunnels, road tunnels, telecommunication tunnels, and deep offices and shelters to protect against air raids. In the mid-l9th century, a comprehensive underground sewer system was built in London, and sewer tunnels probably constitute the greatest share of the UK tunnelling market in the 20th century, often being built to bring 19th century systems up to modern standards. About 150 rail tunnels, of lengths more than about 800m, were built in the 19th century; they included the 7km long Severn Tunnel, opened in 1886 and still in use. The first London Underground line was built by cut and cover, and opened in 1863, and its first line with deep tunnels was opened in 1890. The longest UK rail tunnel is the British section of the 51km long Channel Tunnel. A table gives examples of current, forthcoming, and future tunnelling projects in the UK.