Visit to Kelvedon Hatch Secret Nuclear Bunker

This was our second visit to the bunker and if you missed both opportunities, well, you missed a treat. On our previous visit we had a larger group and were shown around by Mike Parrish, the grandson of the original farmer who was obliged to give up part of his farm so that the bunker could be built. This time there was no conducted tour, but you were given a “wand”, a sort of big telephone handset which you had to operate in the manner explained. You then heard a commentary explaining the various features of your tour.

The building operation involved digging away a whole hill to leave a massive hole which had a layer of gravel many feet thick placed in the bottom. Forty thousand tons of concrete and steel was then fashioned into three floors of rooms and corridors, the outer walls were 10 feet thick and reinforced with one inch thick tungsten steel rods every 6 inches. A Faraday cage (to reduce the effect of radio frequency pulses) and a waterproof membrane surrounded the structure, then all the whole thing was covered up again with the spoil from the hole and an aerial built on the top. The gravel would allow the structure to move but not collapse. This made a structure that would be able to withstand an atomic blast - not too close! Naturally, the whole thing was built in the utmost secrecy, and the locals and even the contractors apparently did not know what the final result was for.

The entrance to the complex was built to resemble a typical Essex bungalow, but was just a little stronger than usual - the roof was a dummy over a five feet thick concrete ceiling! The garage housed a couple of generators of mega proportions which had previously been housed in a “church” a few miles away, but later discarded. It apparently looked as much like a church as the bungalow did a typical building of the area! Normally the system would rely on the national grid for power but could become completely self-sufficient. Sufficient water and fuel oil was also stored for use over a prolonged period.

On entering the bungalow you pass through a steel door and then descend along a tunnel 100ft or so long at the end of which is the original Home Office radio room. This now houses a shack run by the local radio club and Bill Chewter G0IQK was on hand to show us around later. The tunnel was there partly to reduce any blast from explosions but could also fend off any invading civilians who thought they might try to get in! Guns were available in a strongroom for this purpose. Further blast doors, made of tank steel and weighing one and a half tons isolated the main complex. Those inside (600 personnel) would have supplies of food, water, positive pressure purified air and sewage disposal etc. to last three months or so.

Because there were so many people working in the bunker when it was operational, which was from 1952 when it was built to 1994 when it was decommissioned, and there was so much heat-producing equipment, two large refrigeration units kept the temperature comfortable. (Now the temperature is a fairly constant 60 deg.F)

A canteen was available 24 hours a day as people worked in three shifts, and they slept in dormitories, “hot-bedding” so that as one bed was vacated another would take their place.