TRAVELLlNG on the London tube may not seem like much of an adventure. Crowds and smells, the fight for a seat, other people鈥檚 dripping umbrellas, coughs and colds. But one day try cupping your hands to the window glass and staring at the passing blackness. Before long, you will start to notice strange things out there. Tunnels that branch from the main line and disappear, and dark, ghost stations flashing by. You may look for them on the familiar tube map, but they won鈥檛 be there.
The tube has a long history and many secrets. And this is the only part of the subterranean world you鈥檙e likely to encounter in your daily life. But if you let your imagination roam, you鈥檒l find that beneath the earth is a labyrinth of structures, some new, some old, some public and some very private indeed.
London is a good place to begin a descent into the depths. In the last century, when Britain was the world鈥檚 greatest industrial power, its engineers were the first to colonise subterranean space. The upper levels are full of the structures they built, some still working, some put to new uses and some abandoned follies that testify mainly to the wild self-confidence of the era. Deeper down, from our own century, are the structures created by modern tunnelling machinery. Down there are the deep underground trains, tunnels for high-voltage electricity cables and relics of the Cold War, in the secret nuclear shelters of government. That鈥檚 about where London stops. For a glimpse of the next century, we have to travel to Tokyo, where Japan鈥檚 engineers are planning vast underground domes to relieve the stress on their crowded cities.
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But let us begin the voyage to the future in the past, some 30 centimetres below a London pavement. Here lie the relics of a bygone age when information was blown or sucked around London and many of the world鈥檚 other big cities through a labyrinth of tubes. The 鈥渘erves鈥� of the system, were cast-iron ducts that protected smooth, inner pipes made of lead. Messages were enclosed in cylinders made from guttapercha and covered with felt or leather. Powerful steam-driven beam engines would propel or suck the packages to their destination by creating differential air pressures within the 60-millimetre wide tubes.
London鈥檚 pneumatic tube communication system was the most extensive in the world. Its 120-kilometre network was created to overcome problems with the then booming electric telegraph system. At the beginning of the telegraph era, there were no electric exchanges that permitted a message from a suburban telegraph office in one city to be routed directly to a suburb in another. Instead, the telegraph would be transmitted to a main office, be read and then keyed in again for the journey to the other city. Finally, it would be written out and delivered by hand.
As the number of messages sent in London by telegraph spiralled, from some 30 000 dispatches in 1850 to 4.5 million 15 years later, messenger boys and telegraphers were overwhelmed by the number of messages they had to deliver from branch to central telegraph stations. Also, original messages became garbled as telegraphers at branch offices keyed in the words at breakneck speed. Pneumatic tube systems feeding original, paper messages to the central telegraph station proved to be far simpler, and avoided mistakes in the recoding of messages sent from branch offices. The first was installed by London鈥檚 Electric Telegraph Company in 1853.
For a century, the system was an integral part of urban life. Every day, thousands of cylinders hurtled beneath the feet of Londoners at speeds of more than 30 kilometres per hour. Finally, in 1962, the system was closed down, killed by the development of telephones, telexes and automatic teleprinters. The nerve centre, completed in 1874, was the Central Telegraph Office in St Martin鈥檚-le-Grand, now the headquarters of British Telecom. In its heyday, the central office had a staff of 5000 and probably handled 50 000 messages daily. Even in 1957, just five years before it closed, more than 10 000 messages a day were sent whizzing round the network.
The success of pneumatic delivery inspired some wild schemes. Thomas Webster Rammell, a Victorian engineer, became obsessed with the construction of grandiose pneumatic railways for carrying both mail and passengers. The result was the Pneumatic Despatch, an underground railway running from Euston railway station to the General Post Office near St Paul鈥檚 Cathedral, completed in 1869. Carriages were propelled through the tunnels by air pressure generated by fans attached to a powerful steam engine. The carriages sped through horseshoe-shaped tunnels almost 2 metres in diameter, running on rails sunk into the ground. The carriage was fitted with a 鈥渟ailplane鈥� that all but closed the gap between the outside of the cylinder-shaped carriage and the inside of the tunnel.
Rammell was a great self-publicist and, as sections of line were opened, he made sure that journalists were presented with upbeat stories. One press report records that: 鈥淣ot only have letters and parcels been transmitted through the tube, but we also hear that a lady, whose courage or rashness 鈥� we know not which 鈥� astonished all spectators, was actually shot the whole length of the tube, crinoline and all, without injury to person or petticoat.鈥�
Alas, the Pneumatic Despatch proved to be underpowered, and the 17 minutes it took to go from St Paul鈥檚 to Euston saved only four minutes on a fast horse-drawn van. Thus the Post Office never gave Rammell a contract and the project fizzled out in 1882. It vanished into obscurity until 20 December 1928 when parts of the route erupted in a gigantic explosion, hurling a taxi onto its side and making a long crevasse in the road. Gas had collected in the forgotten tunnel and ignited. But the disaster was fortuitous in one way: after nearly sixty years, four of Rammell鈥檚 original rail carriages were rediscovered. One survives in the National Railway Museum in York.
Despite its past failures, pneumatic technology is far from finished. Large hospitals use tube systems to move samples around. And recently some offices and shops, which don鈥檛 want cash lying around close to customers, have begun using it to whisk money away to the safety of a back room. The BHR Group developed a system in their laboratories in Cranfield that could be used in mining and quarrying. Rock spoils would be ferried away efficiently from the face in capsules which pass through tubes subdivided into sections by flaps. 鈥淭he problem with a pneumatic system is that you can only blow something a certain distance, and then it will stop,鈥� explains Ed Broomfield of BHR. 鈥淲e got round this with a repeat valve system involving the flaps,鈥� he says. The technology has never been commercialised but, says Broomfield, 鈥渋t鈥檚 there and waiting, if someone would like to come and wake up Sleeping Beauty with a kiss.鈥�
Which is more than can be said for the other vast Victorian network lying just below road level. There is no hope of awakening demand for high-pressure water because its power can now be more effectively provided by electric motors. But at one time the London Hydraulic Power Company was a winner: dating from 1871, it became the largest enterprise of its kind in the world and remained so for more than a hundred years.
High-pressure water then seemed to be the natural way to distribute power where it was needed. Electric motors were being developed, but the idea of generating electricity at a central power station and using copper wire to carry current throughout a city would not be fulfilled until the early 20th century. Copper was then extremely expensive and many advances in mining and metallurgy were needed before the age of electricity could arrive.
But the Victorians were able to achieve many of the same goals using cast iron and the steam engine, technologies at which they excelled. The steam engines drove the pumps and the cast iron provided the pipes to carry pressurised water throughout the metropolis. It was an economical way to provide power and even helped reduce pollution. Edward Bayzand Ellington, the key figure in the development of hydraulic power, calculated that 500 cranes or hoists, each with its own engine, would together consume 25 000 tons of coal a year. But if they used hydraulic power from a single pumping station, only 2500 tons would be needed. 鈥淭he influence 鈥� on smoke abatement is not to be lost sight of,鈥� he wrote in 1883.
The London Hydraulic Power Company鈥檚 pipes grew from 7 miles to more than 186 miles, from 18 million gallons of pumped water a year in 1884 to 1650 million gallons by 1925, and from one pumping station in London鈥檚 docks to six along the River Thames and one that drew water from Regent鈥檚 Canal.
Besides the cranes, lifts and hoists at the docks, the system powered passenger lifts, car hoists in garages, fire safety curtains in theatres and, in 1920, l77 vacuum cleaners. The hydraulically powered vacuum cleaners fed dirt from the floor through a hose to a 鈥渕ousehole鈥� in the skirting board that led directly into the drains. The arrangement was very efficient, but a connection to the hydraulic power system could be justified economically only by houses of palatial dimensions.
By the 1930s, the network of pipes in London was so comprehensive that it rarely took longer than a week to connect a new consumer living or working in the company鈥檚 catchment area. Then came the Second World War, which proved to be the beginning of the end for the London Hydraulic Power Company. Many of the buildings occupied by the company鈥檚 main clients were levelled. After the war, businesses tended to move away from the centre and new buildings employed electric equipment.
But this was not the end for the city wide network of cast-iron pipes. Hydraulic power鈥檚 long and lingering decline carried it just to the beginning of the age of telecommunications based on optical fibres. In the early 1980s, within a few years of the last hydraulic pumping station closing down, the newly formed Mercury Communications bought the company. It was a 鈥済reat bargain鈥�, says Alec Pettie, manager of the company鈥檚 external works programme in London.
The huge, single benefit of owning the old network of pipes is that Mercury has an automatic right of way in busy city streets that are already densely packed with services. The pipes neatly follow the routes that Mercury needs to reach its customers, most of whom are in the City and in the West End. For long stretches, Mercury could simply feed its fibre-optic cable along the old hydraulic pipes, many of which were in excellent condition. 鈥淚t鈥檚 got us into a lot of areas very quickly,鈥� says Pettie.
The company did, however, have to dig up the roads and pavements to remove valves in the hydraulic pipes, or to smooth out some of the network鈥檚 sharper bends. Mercury鈥檚 work was made much easier by an old wooden filing cabinet it inherited, stuffed full of maps, records, worksheets, annual accounts, brochures, and historical accounts of the London Hydraulic Power Company and its activities. The work-sheets contain meticulous accounts in fine copperplate detailing individual lengths of pipe that have been laid, their sizes and connections. Pipes are rarely more than a few inches from where the plans, some drawn more than a century ago, say they should be.
Mercury is not alone in its aversion to digging up the roads. The world just below street level is extremely congested, with pipes and cables carrying gas, electricity, water, TV, and telephones competing for space. Every time the road has to be dug up, not only is it vastly expensive, but traffic has to be diverted with dire consequences for the life of a modern city. That鈥檚 why, these days, companies are experimenting with ingenious ways to install, replace and repair underground pipes without having to dig long trenches.
British Gas, for example, is trying out ways of bringing old gas pipes up to standard. One method, called swage-lining, is quite simple 鈥� just dig down to one end of an old cast-iron pipe and slide a new polyethylene lining inside. To ensure that the lining fits well, it is drawn through a reduction die with a slightly smaller diameter than the cast-iron pipe as it is fed underground. Once inside, it expands to fit snugly.
The only problem with relining old gas mains in such a way is that the new lining blocks off all the branch connections from the old pipe. To reconnect them all by hand means a lot more expensive digging. Enter the 鈥減ig鈥� 鈥� a generic name for the various kinds of cleaning, inspection and repair objects that travel along pipes. British Gas is designing one that will reconnect homes to a relined mains by working from inside the pipe. The connection pig actually looks rather like a long, shiny metal, articulated toy snake. Each of its tubular segments contains equipment for a particular function: there鈥檚 one with motors and drive wheels, others with various kind of sensors, drilling tools, microprocessors and power packs.
The pig fits inside a gas main that has been relined with a plastic tube. It drives itself along under its own power and searches for branches in the old iron pipe by looking for changes in the flux of a magnetic field created by the powerful magnets it carries. When the sensors pick up a side branch to a home, an on-board computer instructs the pig to move forward until the segment bearing the drill is lined up properly, then it drills a hole through the plastic lining. All that remains is for an engineer inside the house to push a new plastic tube down the side pipe. The end of that tube is drawn to a point so that it slides easily into the hole. The waiting pig senses its arrival and heats up the plastic so that it expands and seals the join. That, at least, is what the pig is designed to do. By next year, gas companies should be able to test its ability to repair a whole streetful of gas pipes.
Other pigs are already used to run along mains pipes to check for corrosion. This time, magnetic flux sensors are used to sense cracks and holes in the pipe rather than side branches. But these pigs are usually drawn along short stretches of pipe by a cable. They are quite unadventurous compared with a larger-species of the same genus which travels along the huge pipelines that run under the North Sea or cross the Canadian wilderness.
Some of these pigs may make journeys of 900 kilometres inside pipes filled with oil or gas, scanning the walls with magnetic flux sensors as they go. They do not need motors 鈥� the flow will carry them along at a walking pace. But they do need to be very strong to withstand the long journeys under the high pressure of the pipeline. They also need very smart, discriminating computers on board. They cannot store all the data generated by examining hundreds of kilometres of pipe, millimetre by millimetre, but must process it immediately and keep only the parts that identify cracks and corrosion.
Leaving the smart pigs to struggle with the complex problems of connecting pipes on the surface to distant gas fields, we can descend deeper into the ground. In fact, the drains running along the street are a convenient entrance to the main sewers that run deep down beneath London. This is an altogether dirtier and more dangerous world. No one ventures down to look after them except in teams of between five and eight, equipped with protective clothing and gas sensors. So the sewers too are fast becoming home to robot vehicles and automated repair systems.
London has been lucky because it has had little need for massive engineering work for a long time. That鈥檚 because its sewers were built on a robust and generous scale by Joseph Bazalgette, one of the greatest Victorian civil engineers. In 1853, when Bazalgette was appointed chief engineer of the Metropolitan Commission of Sewers, the city was in crisis. Sewers drained straight into the Thames. The river was thick with excrement and its banks coated with layers of putrid sludge from untreated waste.
In 1858, the 鈥淕reat Stink鈥� was so bad that MPs were forced to abandon the newly constructed House of Commons. Bazalgette鈥檚 solution was a vast system of interceptory sewers that ran from west to east on both sides of the Thames, cutting across the old sewers which ran down to the river and taking their waste out to the east of the city.
Here, far from the capital, the waste was at first discharged untreated into the river. But in 1878, the paddle steamer Princess Alice collided with a coal barge near Barking. Most of its passengers should have been able to swim to the shore, but the river was so thick with sewage that 623 people vanished beneath the slime. Only five or six people survived. Rudimentary treatment plants were built soon after.
Since then, while the pattern of the sewers has remained much the same, two things have changed. First, it is now seen as too expensive and dangerous to send teams of men down the sewers to check and repair them. Even as recently as the mid-1980s, 300 men known as 鈥渇lushers鈥� worked in London鈥檚 sewers; now there are only 80. Much of their inspection work is now being done by small, remote-controlled tractors bearing lights and video cameras. Secondly, the system now has to deal with wastes unfamiliar in Bazalgette鈥檚 day.
A walk underground in one of the safest and cleanest sewers 鈥� from Hyde Park past the French Embassy鈥檚 outfall through the heart of Knightsbridge 鈥� gives you a taster. Along the way you pass weirs, steep gradients where you must fight the flow of water, and small piles of accumulated debris, most noticeably condoms and tampons. You also find rogue connections: in the roof of a chamber near the overflow from the Serpentine, a pipe has simply been punched through from the outside by workmen in the park who wanted an instant drain.
Video pictures show in detail what happens elsewhere. Every year, between 600 and 800 kilometres of sewer are surveyed by CCTV 鈥渢ractors鈥� in the Thames region alone. These tractors send back pictures to an operator sitting in a van on the surface. On screen are a variety of grotesque problems. There are blockages caused by an accumulation of fat, pipes that are deformed, cracked or 鈥渟trangled鈥� by tree roots, and broken walls where taproots have punched their way through. And then there are other service pipes which have simply smashed straight through the sewers.
The fat deposits building up in some of London鈥檚 sewers are a peculiar new problem, stemming from burger joints and other fast-food outlets. Leicester Square and Piccadilly are among the worst fatspots. 鈥淚t is an increasing problem,鈥� says Alan Lenander, Thames Water鈥檚 operations manager for West London鈥檚 sewers. Some of these places have even taken to macerating their leftovers and putting them down the drains. The problem wouldn鈥檛 exist if Westminster Council, like some others, insisted that restaurants fit grease-traps to the drains. These skim off molten globules of fat. Add bacteria to the stuff and they will digest it for you.
For now, however, the flushers have to go down and dig it out by hand. 鈥淚t鈥檚 like concrete. It鈥檚 the worst job these guys have to do,鈥� says Chris Bosher of Thames Water鈥檚 research and development department. 鈥淭here are instances where we鈥檝e had between 30 and 40 inches solid where you could barely push a stick into it.鈥� Bosher and his colleagues tried to work out whether fat-digesting bacteria could loosen the blockages. They built an artificial sewer at their base in Reading, and filled it with fat taken from blocked sewers. Unfortunately, the bacteria didn鈥檛 work.
Bazalgette did not anticipate problems like this. Nor was he aware of the dangers to come from the internal combustion engine. In April 1992, a series of explosions in Guadalajara destroyed 20 blocks, killing 190 people and causing $300 million worth of damage. A pipeline run by the state-owned oil company Petroleos Mexicanos had leaked into the sewers.
All British petrol stations have an interceptor, to prevent petrol discharging into the sewers. But accidents can happen. Earlier this year, disaster nearly struck in Pinner Green in north-west London when heavy rain flooded the petrol tanks and overflows at a petrol station, causing a mixture of petrol and water to leak into the drains. Lenander took the call, and within 20 minutes, a fire crew and local authority employees had put stoppers in the surface drains to contain the spill. 鈥淎 Guadalajara-type incident could have happened,鈥� says Lenander.
While the problems caused by fat and petrol still call for human intervention, ageing sewers can be dealt with by using similar tricks to those employed by the gas companies. New plastic pipes can be squeezed inside, or a long sock, coated in resin, can be placed over the mouth of the sewer and blown inside out by pumping water into it. Once in place, hot water ensures the resin hardens and bonds to the sewer wall. And once the new lining is complete, a CCTV tractor with a rotary cutter can be used to cut through the lining to reconnect side pipes.
Bazalgette鈥檚 intercepting sewer system runs at depths that occasionally pass the 20 metres mark, well beneath the complex pattern of pipes just below the pavement that provide services to homes and businesses. But even at 20 metres, there is still not much space. Here, at the top of the middle layer of the underground world, there are tunnels for high-voltage electricity cables, like those running 2.1 kilometres from Leicester Square and 1.5 kilometres from the City of London at a depth of 25 to 30 metres. And there are the deep foundations for large buildings. When London Electricity was building the City tunnel it had to navigate among the deep piles supporting the Barbican high rise complex. At one point its 2.0 metre-diameter tunnel passed within 50 centimetres of foundation piles on each side.
The Royal Mail is down here, too. Shoppers in Oxford Street have no idea that the world鈥檚 first automatic electric railway is zipping along some 20 to 25 metres beneath their feet. 鈥淚t was opened on 5 December 1927, and has scarcely been changed since then,鈥� says Colin Tipp, the engineering manager for the 鈥淢ail Rail鈥�. It takes the individual trains as little as 13 minutes to complete the 11-kilometre track between Paddington Station and Whitechapel, dropping off mail at intermediate depots on the way. Mail Rail handles around 23 000 bags per day, averaging 250 letters per bag. 鈥淚t keeps 300 van runs off the streets, and those vans would have to make those runs in what is already a congested city,鈥� explains Tipp.
To complete this crowded layer, there are the 32 kilometres of shallow tube lines. These lines include the route of the world鈥檚 first underground railway, opened by the Metropolitan Railway Company on 10 January 1863, and running 5.6 kilometres from Paddington to Farringdon. Like other shallow tubes in the Metropolitan, Circle and District lines, it was constructed by the so-called 鈥渃ut and cover鈥� technique, in which a deep ditch was dug for the railway then covered over.
The tubes take us naturally on again downwards, to the deep tubes, which were tunnelled through the blue clay well below their cut and cover cousins. Their 139 kilometres of tunnels are 24.4 metres below ground on average, but passing through Hampstead Hill go to 67.4 metres.
Aboard the tube, we enter the only part of the underground world that is familiar to every Londoner. But even here there are some surprises. Central London has five ghost stations. Among them are Down Street, which was converted during the Second World War into a bomb-proof bunker from which the railways were run and British Museum, closed in 1933. Then there is Brompton Road which the police won鈥檛 let you anywhere near because they found a dead body lying there just before Christmas. And hidden away down one branch is King William Street, one of the termini of the world鈥檚 first true underground train services which began in 1890. But London鈥檚 abandoned stations have not been used as imaginatively as one on the Paris Metro. There the lights were left on, the platforms painted in the bright colours of a sunlit beach and deckchairs set out. Passing commuters had a fleeting glimpse of summer holidays to come.
At the level of the deepest parts of the tube system, the familiar services slowly give way to the altogether more secretive. Much of what is down here 鈥� at least what we know about 鈥� is the work of a 55-tonne tunnelling machine called Dorothy. Over the past five years it has dug out part of the Thames Water Ring Main, at an average depth of 40 metres; now it is at work on another deep tunnel, being built to carry electricity cables from south London to the centre. Last year, the first 6 kilometre section was completed 35 metres below the surface.
The ring main is the longest tunnel in Britain, running 80 kilometres in a vast loop from Ashford Common in Surrey under Regents Park and back around to its beginning. There was a simple reason for building the main. Most of London鈥檚 water comes from the Thames Valley, well to the west of the city. To get sufficient supply of water over to the east of the city through the vast network of surface pipes means maintaining a high water pressure at the west. That means lots of burst pipes.
The ring main solves the problem by putting water into the system at 11 different points across London. At each is a pump shaft capable of moving water from the ring main to the surface at the rate of 50 000 litres a minute. With a diameter of 2.5 metres, the capacity of the ring main is vast and can supply 1300 million litres of water a day. But it still suffers from some familiar problems. Just as turning on a domestic tap can cause knocking in the pipes, so starting the pump can create a pressure wave that travels through the water causing a gigantic 鈥渂urp鈥� as it passes through the tunnel. To stop the burp bursting the pipes, the water level can rise up surge pipes at each shaft. These act like shock absorbers damping the pressure waves as they pass.
Even at the depths of the ring main, tunnellers cannot dig just anywhere. London Electricity, which is currently heading towards central London with its tunnel from Wimbledon to Pimlico, needs permission to pass beneath private property. More crucial is to obtain the blessing of BT and the Ministry of Defence. 鈥淚f the route passes too close to one of their tunnels, they can refuse permission,鈥� says Simon Stroud, an engineer with the company that manages the project. 鈥淭hey do not even say where the two tunnels coincide but we still have to come up with an alternative.鈥�
The Jubilee Line tube planners have had similar experiences to those at London Electricity. They have had to change course more than once to avoid damaging secret tunnels and bunkers around Whitehall. In theory, says Stroud, it might seem possible to map the Ministry of Defence鈥檚 underground facilities by revising and resubmitting the plans many times. 鈥淏ut you only get three chances. Then they refuse permission altogether,鈥� he explains.
No one is going to own up to whatever is down there, but we can make educated guesses about the underground life of a post-apocalypse government based on outdated secret shelters. There鈥檚 General Eisenhower鈥檚 wartime headquarters under Goodge Street from which he commanded the Allied forces in Western Europe, the atom bomb-proof telephone exchange under Chancery Lane tube station, and the Kelvedon Hatch nuclear bunker in Essex, the seat of government for the London area in the event of a nuclear war in the 1970s or 1980s. None are currently open to the public.
During the Second World War, an extra set of platform-sized tunnels was constructed deep under eight Northern Line stations to provide deep air raid shelters. The plan was to join them up to provide an underground express service running parallel to the Northern Line. Eisenhower commandeered the one beneath Goodge Street for his secret headquarters. It is now used as a security archive.
Eisenhower fitted express lifts which run on direct current for fast access to the tunnels which are more than 40 metres deep. In a cupboard near the top of one of the lift shafts is a mercury arc rectifier which converts AC to DC. The device is a large vacuum tube, slightly bigger and more elongated than a human head, filled with mercury vapour which emits an eerie glow as fingers of purple plasma continually caress the inside of the tube. In the 1960s, the BBC used the device to represent the sinister brain of an evil alien in an early episode of Dr Who.
During the war, two other large, deep bunkers were also built at Chancery Lane and St Paul鈥檚. In the early 1950s, the tunnels under Chancery Lane tube station were converted into a secret telephone exchange to handle government communications during wartime. Forty metres below ground, the tunnel was toughened to resist an atomic attack on London. There was room for eighty phone engineers, food for six months and a supply of water from an artesian well dug beneath the exchange.
The site now stands empty. Although secure enough for the 1950s and 1960s, it is not deep and strong enough to withstand precise targeting by hydrogen bombs. And digital exchanges made much of its equipment obsolete. But although unused, BT is not willing to show the site or even talk about it. That might be because the site is connected to a network of very deep tunnels, big enough to walk through, and known to run for at least 19 kilometres across London. Apparently, the tunnels carry telephone trunk cables. But no one knows what other uses they have been put to, or what else they connect with.
There are widespread rumours that a very deep shelter has been built beneath the Ministry of Defence, for example. If it exists, the closest we might get to knowing what it is like might be by paying a visit to Essex. Perched amid woodland on the side of a small hill near the village of Kelvedon Hatch, lies a modest brick bungalow. During a national emergency, it would have housed armed guards who might well have shot you if you had sought shelter. But if you had been one of the 300 officials deemed vital to the running of the region after a nuclear attack, you would have passed through the front door into a small shower room, with a little sign saying 鈥淒econtamination Unit鈥�. Here you would have got rid of your clothes and showered away any radioactive dust.
Behind, a set of stairs lead down to a broad, brightly lit corridor that heads more than 100 metres into the heart of the hill behind. At the end is a giant metal door weighing more than a tonne, leading into a three-storey underground bunker. Its concrete walls are 3 metres thick, strengthened with tungsten rods, and the whole structure rests in a deep layer of gravel designed to absorb the shock of a nuclear blast. Set into the hill above the bunker are 鈥渂urst caps鈥� 鈥� layers of concrete which would divert the energy of a close hit. All telephone and electricity cables entering the building have built-in slack to allow for the seismic shocks from a nuclear attack. The entire structure 鈥� 30 metres high and up to 30 metres wide 鈥� is enclosed in a steel-mesh Faraday cage which would have prevented damage to computers inside the shelter from the electromagnetic pulse accompanying a nuclear explosion.
Inside are kitchens, dormitories, showers, toilets, telecommunications rooms, a radio broadcast studio and enough supplies to feed 300 people for 8 weeks. But there is nothing of the atmosphere of Dr Strangelove. Apart from the lack of windows, the interior is remarkably like the standard-issue Whitehall office of the 1960s, with its greeny-blue paintwork, and bright, neon strip lighting. It is a microcosm of the world it left behind 鈥� perhaps a deliberate attempt to normalise the unnormalisable. One room is marked 鈥淯niformed services 鈥� no entry鈥�. In another large, open-plan office, a single desk is reserved for each government department. Large signs on the wall read 鈥淢inistry of Agriculture, Ministry of Power鈥� and so on. Just one small room was reserved for scientists. Scattered about are copies of the Scientific Intelligence Officers Operational Notes with chapters on 鈥淏omb identification and plume separation tables鈥�, and 鈥淪tandard methods of calculating fallout data鈥�. Another room, with a single narrow bed, is reserved for the Prime Minister.
Power for the bunker was originally supplied by two huge generators housed more than a kilometre away in a brick building disguised as a village church. Later, the two diesel generators were moved into the bunker and an underground fuel tank was built at the surface. The generators power a large air conditioning system that can purify the atmosphere before pumping it through the bunker.
There were four of these so called R4 nuclear shelters, intended as key commands for governing different parts of Britain. But they were just a part of the network of bunkers. There were 20 underground two-storey R3s and hundreds of one-story Rls. Although the locations have not been made public, most would not be too hard to find. The interesting question, of course, is what has replaced them. It鈥檚 very unlikely that because the Cold War is over the British government no longer maintains a bolthole. The various R bunkers were, in any case, becoming outmoded before the Cold War ended, and their replacements must have been built.
Where are they? Naturally enough, no one is saying. For the future of deep underground living, we have to leave London and head to Tokyo. Here, engineers are planning to build huge underground domes 40 metres or more beneath the city. Their work is not secret for the move underground is driven by the fear of soaring land prices, not falling nuclear rockets.
During the 1980s, a combination of economic boom and wild speculation pushed land prices in Tokyo to the insane point where the gardens containing the Emperor鈥檚 palace were estimated to be worth more than the whole of California. Not surprisingly, government officials at the Ministry of International Trade and Industry began to look for new sources of property beneath the ground.
Unfortunately, the immediate subsurface is already very crowded. Along with the usual network of pipes, sewers and trains, Tokyo also has an extensive system of underground streets. It is possible, for example, to walk nearly 4 kilometres across central Tokyo entirely underground, passing along subterranean avenues selling everything from high-fashion clothes to cheap noodles. Osaka goes one better with an underground shopping city built on two levels with a river, waterfall and a small lake, complete with plastic swans.
The goal of MITI鈥檚 Underground Space Development Project is to build 鈥済eodomes鈥�, 50 metres in diameter and 30 metres high, some 40 metres below the surface. Although the mining industry has excavated large caverns in rock at far greater depths than this, no one has attempted to build such large structures in the soft soil that underlies Tokyo and many other large cities. To makes these structures possible, new kinds of automated digging and tunnelling equipment capable of working underwater in flooded soil must be developed.
Engineers working on the project say that construction of a geodome will begin with a vertical shaft. Into it will be lowered a cutting machine designed to dig a tunnel in a tight spiral. The machine will cut an expanding spiral which maps out the roof of the geodome, then a contracting spiral for its base. A second robot machine runs along this tunnel, drilling and inserting bolts to reinforce the dome. Finally, the plan is for automatic digging machines to excavate the rock within the structure and then coat it with a concrete lining.
The project has now been running for four years. Models of the spiral cutting machine and underground excavator have been tested. And the first experimental half-sized dome is now under construction 50 metres beneath Sagamihara City, on the outskirts of Tokyo. But how quickly will geodomes become a normal part of city life?
When the project was first proposed, it was accompanied by futuristic paintings of dozens of domes beneath Tokyo linked by deep underground passages. MITI now says that construction is linked to land prices. If they go up again, then the first geodome could be ready early next century. But even MITI is not expecting people to live underground. Instead, they would like to move services such as gas storage and electricity generation underground so that there would be more space for people up above.
And if the geodomes don鈥檛 take off, MITI is not too worried. The new robot machines they are developing will be able to work underwater. They will always be useful in excavating harbours, digging railway tunnels and providing other kinds of underground structures for the 21st century.