Tag archives: royal observer corp

The Royal Observer Corps (ROC) was a civil defence organisation operating in the United Kingdom between 29 October 1925 and 31 December 1995, when the Corps’ civilian volunteers were stood down.Comprised mainly of civilian spare-time volunteers, ROC personnel wore a Royal Air Force (RAF) style uniform and latterly came under the administrative control of RAF Strike Command and the operational control of the Home Office.

Originally there were some 200 observation posts throughout the country and their role was to provide visual detection, identification, tracking and reporting of aircraft over Great Britain during the World Wars. Early Observation Posts were often crude and un-fortified but during the war many were rebuilt from brick and had sandbag defences.

On 12 May 1945 when the German Luftwaffe had ceased combat operations the ROC stood down, however it wasn’t long before the threat of Cold War arose and the ROC were reinstated.

In 1957, the United Kingdom Warning and Monitoring Organisation (UKWMO) was established under Home Office control to provide essential information about impending nuclear attacks to both civilian and military authorities.So that the ROC could work with the new type of threat the old monitoring posts were replaced with something that had protection from nuclear blasts.

Between 1958 and 1968 a countrywide building programme resulted in a network of 1,563 underground monitoring posts, approximately eight miles apart, distributed throughout England, Scotland, Wales and Northern Ireland, at an estimated cost of almost £5,000 each.The bunkers were built by digging a 25 feet deep hole, placing a reinforced concrete bunker in the hole and then burying it under compacted soil.A single hatch to the surface was the only entrance/exit with a 20 ft vertical ladder that lead to an underground chamber 7ft x 16ft x 7ft high.Posts were typically grouped together in threes or sometimes four, to form a cluster. One post in each cluster was a master post and could communicate directly back to ROC Control using a Tele-Talk device connected to ROC Group HQ and the Carrier Warning Receiver.

No telephones were provided. Each ROC Post was manned by 2 to 3 people who ate and slept in very primitive conditions as there was no electricity or running water in the bunkers, toilet facilities were by way of an Elsan Chemical Toilet located at one end of the bunker.

The ROC Post had a variety of external equipment fitted as standard:Bomb Power Indicator (BPI) – This would register the pressure wave from a nuclear explosion passing over it and the results were read on a dial inside the ROC Post.

Ground Zero Indicator (GZI)– Basically a crude pinhole camera that could ‘photograph’ the fireball of a nuclear explosion.Radiac Meter – Used to count radioactive particles
Fixed Survey Meter (FSM)– Replaced the Radiac Meters and used to detect nuclear fallout. (The FSM could be safely operated without leaving the bunker)Cross section of a ROC Post