The remains of wartime infrastructure litter these Islands - a reminder of a long, long history of conflict and strife. But time has softened their presence, smoothed away their proud and pragmatic violence - weathered stone and rusted metal, exhibits in museums and tours for smiling tourists. War through time has ever laid heavy on the innocent, but what do we see of it now, how do we feel it here? So distant, in time and place. So very far away.
And yet. There was a time, of course, when war was with us, and walked amongst us, brazen and grinning. The 20th century brought war to our towns and cities, to our villages. Mass destruction and misery. And as the 20th century ground its weary way through these Islands, we perfected the means to destroy on such a scale as to be almost - almost impossible to process. The Cold War was born from the embers of the Second World War, petrol thrown on a smouldering bonfire. The horrors of nuclear conflict became reality.
The remains of the Field Survey Meter in the foreground - measuring the amount of radioactive fallout.
Above Llangollen, within a field, much like any other field, is a brittle little bit of Cold War history - an Underground Monitoring Post, built not to protect us from falling nuclear bombs or missiles, but simply to measure the damage, to quantify the horror inflicted. Most of it is below ground, with the unassuming, slowly rusting, paint peeling and flaking remains of the vent shafts and monitoring equipment all to indicate its sinister presence. And there is something about that inherent incognitos which is teeth grindingly unpleasant, which is hard to render acceptable in beautiful Llangollen. In a field below Castell Dinas Bran.
In 1955, the British Government commissioned the Strath Report, in light of the growing realisation that the power of atomic weapons had changed the landscape forever.1 The Report indicated that in the event of a ‘limited’ atomic attack on Britain, the result would be utter devastation. It found that an attack with 10 hydrogen bombs would likely result in 12 million deaths,2 half of Britain’s industry destroyed, food and water resources largely poisoned for some time and no part of the country free from the risk of radiation contamination. It was also made clear that Britain’s defences against such an attack were largely non-existent. The emphasis turned from prevention to coping with the aftermath.
The dome on the vent stack suggests that the Llangollen UMP was the master unit.
The Royal Observer Corps was in effect resurrected in order to organise Britain’s response. The ROC had found itself largely irrelevant with the advent of fast, supersonic jets, which made traditional observation of incoming aircraft a ‘blink-and-you’ll-miss-it’ experience. Instead, in many cases, as it would seem at Llangollen, the existing aircraft observation posts (most built during the Second World War) were demolished and Underground Monitoring Posts built in their place. Many hundreds were quietly built, their presence unadvertised and inherently sub rosa.
The construction methods were unsophisticated. Simply put, a huge hole was dug and a concrete box, some 5.8m by 2.6m by 2.3m was built within. Holes were cut into the roof for the various vents and monitoring equipment that linked the post with the surface, and the whole unit was pitched to limit moisture. Sometimes the walls were coated in polystyrene to provide insulation from the cold. The post was then covered with at least 1m of earth. The whole thing was then fenced off, but curiously not to the extent that you might think for such a facility. There would seem to have been a sense that to do so might bring the post to the attention of all and sundry. Instead, these posts seem to have been allowed to slowly recede into obscurity. They do not appear on Ordnance Survey Maps - at least as UMPs, since sometimes they are identified as covered reservoirs. There is something quite inherently British about this that I cannot quite put my finger to.
The interior of the UMP conformed to a standard plan - functional, with few creature comforts. 3
The role of the UMP was three fold. The Ground Zero Indicator measured the direction and height of the nuclear flash, while the Fixed Survey Meter measured the amount of radioactive fallout. The power of the initial blast was measured by the Bomb Power Indicator. All this information would be sent on to Group Headquarters, where all the data would be triangulated, assessed and then passed onto other agencies, including, where appropriate and necessary to the public through the BBC.
Underground Monitoring Posts were collected together with others nearby into groups of three or four, with one of the posts built as a master post, with a VHF radio set. The presence of a ‘dome’ on the vent stack at Llangollen would suggest that it was the master post of a group which incorporated the UMP’s at Brymbo and Ruthin.
Built in 1958, the Llangollen post was closed with what was believed to be the end of the Cold War in 1991. The remains of the post are not in anyway extraordinary - they are much the same as you will find at a very many other UMPs throughout the country. The entrance is locked but earlier reports suggest that the interior has been almost completely stripped of all workings other than a BT junction box. The exterior conforms to the standard plan of the vast majority of UMPs. It is possible to see the remains of the Ground Zero Indicator upon the entrance block, the stripped back Field Survey Meter, the Vent Stack, with its dome, and the concrete base of the Bomb Power Indicator. The concrete foundations of the original aircraft observation post are also available. The whole site is one of faded, industrial purpose, with its flaking green paint and rusting metal this and that.
UMPs were almost always fenced off, without being ostentatiously threatening.
It is quite the experience to come upon it in this field, the cold stone might of Castell Dinas Bran in the near distance. I can only tell you how I felt when I walked about it. There was a thrill, of course, at finding it here. I wouldn’t do this without the promise of the thrill. But, I will be honest with you - I wasn’t comfortable that it was here. In my Llangollen. Of all places.
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Footnotes
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1 Britain had joined the United States and Soviet Union in the ‘Club’ as a Nuclear nation in 1952.
2 Britain’s population in 1955 was slightly in excess of 50 million.
3 This is not my drawing. For the very life of me, I cannot remember where I found it. If anyone can shed any light on this, I would of course wish to seek permission to use the illustration and credit the artist. Until then, I have a right cheek, me.
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Further Reading
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Subterranea Brittanica ~ Nuclear Monitoring Posts
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