The Cold War stand off between the USA & Soviet Union meant the fear of a Russian nuclear attack was never far away. The British Government required a base to lead from should the feared nuclear attack materialise. The building of four large underground bunkers (known as R4's) was ordered.

The construction of these bunkers was an immense undertaking. The ground was excavated to a depth of 125ft. A layer of gravel 20ft thick was then used as a shock absorber to cushion the shock wave from any nuclear blast. The supporting walls were 10 ft thick and had tungsten reinforcing rods placed at 6 inch intervals for additional strength. The outer walls were then covered in brickwork, over which a layer of wire netting had been placed and soaked in pitch. Not only would this help prevent water ingress, it would also make the perfect "Faraday Cage", thus preventing any electronic equipment housed inside the bunker from being susceptible to the Electro-Magnetic Pulse caused by nuclear detonation. All internal doors were also lined with metal to aid the protection of the equipment. Concrete rafts were placed on top of the structure, followed by 15 foot of soil to add extra protection.

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Key

The sites for the four bunkers were Box, Shipton, Bawburgh and Kelvedon Hatch. The Kelvedon Hatch bunker was only 25 miles from central London, and 6 miles from the North Weald RAF base. The bunker was completed by 4th August 1953.

An innocent looking woodland path, leading to the secret bunker.

At the end of the path, a fairly conventional bungalow. Or is it?

The roof is, in fact, solid concrete.

An ordinary bungalow or an entrance to a secret nuclear bunker 
built to protect the British Government? You decided. *

The entrance corridor leading to large steel blast doors. *

Space is limited underground. Bunk beds are situated even in corridors. *

These generators were used to provide electricity to power the bunker. *

The BBC radio room. This would have been where the Prime Minister 
would have spoken to [the remains] of the British nation. *

Teams of civil servants would have co-ordinated county council's response
 for up to two months after the initial attack. *

The Prime Minister's Personal Quarters *

The back entrance to the bunker. If the main blast doors were blocked this was the only other way out. If this was blocked, there was no escape. As the bunker was secret, no one would come to rescue the occupants.......
no one would know they were there.

A small communication mast would have been used to communicate to local authorities. Telephone wires buried deep underground would have provided a vital link to other Government bunkers, and the armed services.

To enable the occupants of the bunker to communicate with the outside world a large mast was constructed several miles away, so as not to attract attention.

* These Kelverdon Hatch pictures © Target Communications
01227 365344

As well as these large, strategic bunkers, smaller constructions were erected at numerous points around the county. One, which until recently, was open to the public was...

Furze Hill bunker is an example of an Anti Aircraft Operations Room (AAOR) bunker. Twenty-seven of these were initially built around Britain. Their role was to act as command centres for the deployment and firing of anti-aircraft batteries. Construction of the bunker began in 1951. The project cost £500,000, which in today’s terms would equate to around £18,000,000. 

The advent of the jet engine, which allowed an enemy aircraft to approach more rapidly than a propeller driven aircraft, effectively made these sites all but redundant by 1954.

Although the bunker was not constructed to survive a direct hit from a nuclear weapon, the walls are 2 ft thick, re-enforced with steel mesh. The roof is around a three foot thick, and the foundations are approximately nine foot in depth. All entrances are protected by heavy blast doors made from military grade tank steel.

If warning of an attack came the bunker would have been hermetically sealed and those inside would have begun the task of co-ordinating vital emergency services within the County and plotting the sites of bomb bursts.

Obviously, nuclear fallout would be a real danger to those within the bunker should particles of radioactive elements get into the bunker. The ventilation & air conditioning were vital to ensure the safety of those working within. Normally fresh air would be drawn into the site from the outside. This would be warmed or cooled as required dependant on the ambient temperature. During a nuclear attack the air in the bunker would be automatically recirculated and cleaned by large filter banks. During recirculation all the air in the bunker would be cleaned once per hour. This system would be able to provide "fresh" air for the occupants of the bunker for up to twenty days.

Once an attack had taken place the civil servants would need to  communicate with emergency services, the military and Government. This communication would have been conducted using telephone cables buried deep underground, and shielded from the effects of a nuclear explosion. The bunker had its own telephone exchange. This exchange originally housed "dolls eye" manual exchanges. However, a refit which took place in 1980 removed this system and replaced it with the more modern digital exchange. These allowed over 500 outside lines to be connected to over 150 internal extensions within the bunker. The sensitive electronics used by the exchange were housed in special green cabinets which shielded them from the effects of the EMP pulse produced when a nuclear devise is detonated.

Plotting Room

The map room would be used to plot all bomb bursts in the locality. As reports were telephoned in by official observers scientists could calculate the exact location, strength and effects of the blast. This data would then be collated with predicted weather patterns from the MET Office. Thus allowing the scientists to calculate where any fallout would be likely to spread too.

Dormitory

When fully manned the bunker would hold around 90 – 100 personnel. There was not enough space for the construction of dormitories large enough to accommodate so many people. Thus a system of hot beds was used. This simply meant that personnel took it in turns to sleep for six hours in the beds available, after this time they would return to their stations and a colleague would then use the bed for his or her six hours of rest.

Planning & Co-ordination room

The centre of the bunker housed the Central Operations Room. This was the nerve centre of the establishment and it was from here that all the available data from the outside would be analysed and acted upon. Representatives from each County Council department would liase with officers from the military and fire, ambulance and police services. This room contained the infamous war telephones which, should an attack have been imminent would have received the three minute warning.

Radio Room

The radio room was used to monitor radio traffic and although any broadcasts from the bunker would have been send via telephone lines to the main transmitters located several miles away, should these have been damaged or destroyed, then smaller back up transmitters could have be utilised.

County Controller

During a time of heighten tension the UK would have been divided into 18 regions. Each would have its own Regional Government HQ (RGHQ), which would have been used to co-ordinate and administer Government business up to and after an attack. The RGHQ would have been controlled by a senior civil servant, who in turn, would have taken orders directly from the UK Combined HQ, Cabinet War Office or from the chief’s of staff or Prime Minster located in an airborne command centre.

Comcen

The Communication Centre (Comcen) would be the hub of all communications both into and out of the site. Vast amounts of stationery were stored here, and as information poured in it would be sorted and taken around the building to the relevant departments.

Visit the links page to find out more about nuclear bunkers which are open to the public.