Role of the U.K.W.M.O.

United Kingdom Warning and Monitoring Organisation


The body known as The United Kingdom Warning and Monitoring Organisation (U.K.W.M.O.) was set up in 1957 to warn the general public, government and the military of any impending nuclear attack on the U.K. Its other role was to warn of fallout from nuclear weapons affecting the U.K. Even if the UK wasn't the intended target, fallout from detonations in Europe may affect our territory. The Royal Observer Corp, who had served the country well in World War 2, became the eyes and ears of the UKWMO.
During the life of the UKWMO, the UK Civil Defence went through a number of phases. In 1968 the government reduced the spending on Civil Defence and disbanded the Civil Defence Corps, Auxiliary Fire Service (AFS) and the Industrial Civil Defence Service (ICDS). Civil Defence continued on a care and maintenance basis only. A reorganisation in 1972 shaped Civil Defence into the structure described on this site. The Thatcher Government of the eighties increased its spending on armaments and Civil Defence. This led to modernisation of the Home Defence and Emergency Communications networks, no sooner was this completed the Cold War came to an end. Only the AFS Green Goddesses were retained in mothballs and used during various Fire Brigade strikes until being sold off in 2004.
When the political changes in the Soviet Union signalled the end of the Cold War, the closure of the UKWMO was announced in the U.K. Parliament on 12 November 1992. All the warning systems described on this site were dismantled and the bunkers sold off.

Outline of Role

A possible attack would be notified to UKWMO officers stationed at High Wycombe or Preston who would issue a national attack warning to the public via the HANDEL network and radio broadcasts. If the ROC monitoring posts detect a detonation before a national warning was issued, procedures were in place to ensure a retrospective attack warning was given. Should the attack fail to materialise or not involve nuclear weapons, a national all clear would be notified in a similar way.
Fallout warnings would be issued locally by the UKWMO and be relayed to the public via the carrier network and radio broadcasts. This data would be shared with the Regional Government Headquarters, Local Authority Emergency Centres and Military Nuclear Reporting Cells to enable these to control the post strike recovery operation.
After the attack, when radiation levels in a particular area had dropped to a safe level or if an area wasn't affected by fallout, an all clear would be sounded by sirens and radio broadcast stating which areas were now considered safe for people to emerge from their shelters.

How the UKWMO fits into the U.K. War Emergency Structure

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A Brief History of the ROC

ROC Badge
The foundations of the Royal Observer Corp were laid between the first and second world wars. At the start of WW2, the Observer Corp as they were known then, were mobilised and observation posts were continuously manned from 3 September 1939 until 12 May 1945. In recognition of their role in the Battle of Britain, in April 1941 the Observer Corps was granted the title 'Royal' by King George 6th.
When the United Kingdom Warning and Monitoring Organisation (U.K.W.M.O.) was set up in 1957 to warn both the military and civilian population of any impending air attack, the job of the Royal Observer Corps (ROC) in the nuclear era was to report the positions of the bomb strikes and monitor resulting fallout areas.
Throughout the Cold War the UKWMO staff and the ROC were separate organisations. The U.K.W.M.O. was run by the 'Home Office' in England and the 'Scottish Department of Home and Health' in Scotland through part time civil servants. The ROC continued to be part of the RAF and administered by the Ministry of Defence. Command of all sections resided with the non-uniformed UKWMO staff. The attack warning and subsequent fallout warnings were assessed by the scientific members of the UKWMO. ROC members played no part in any assessment or decision making within controls.
At the time of the creation of the UKWMO in 1957 the ROC consisted of 40 Observer groups with 1563 observation posts. In 1968 the Labour Government spending cuts saw the disbanding of the Auxiliary Fire Service, the Civil Defence Corps and some elements of the Territorial Army and Volunteer Reserve. The ROC was reduced in size to 873 underground posts and the staff halved. A further rearrangement of boundaries occurred in 1973 which reduced the organisation to twenty five groups. This left each ROC Group with thirty to forty observation posts within its control.
Each ROC post making frequent observations and forwarding them to group headquarters. At Group the raw data was processed to generate bomb detonation locations then estimated yield (bomb size) were calculated. Taking into account factors like bomb size and wind direction, the UKWMO would make fallout predictions. Live radiation readings from ROC posts were used confirm the path of fallout and amend the prediction if necessary.
The UKWMO was arranged in Five Sectors containing Five Groups, the Sector Headquarters was colocated with one of the Groups. Groups forwarded their observations to Sector who would collate this to create a national picture. Sectors had links to our European neighbours civil protection authorities to exchange information about fallout that may affect other countries. The organisational structure set in 1973 remained fairly static until 1991.
Following a Home Defence review, government spending on the UKWMO increased during the 1980s, resulting in many improvements to equipment and especially communications. By the time this new equipment and public warning system had rolled out by the late 1980s massive changes were occurring in the Soviet Union. The threat of nuclear war was receding.
On the 10 July 1991, the current Home Secretary Mr Kenneth Baker, announced to parliament that the services of the United Kingdom Warning and Monitoring Organisation were no longer required. Its field force, the Royal Observer Corps would be 'Stood-Down' on 30 September 1991.
Former members meet socially via the Royal Observer Corp Association, (ROCA). Many of the monitoring posts have been left derelict but a small number survive thanks to the dedication of a few individuals who have lovingly restored them. Many of the Group controls have found other uses and some have been demolished for housing. In Bedford, for example, Observer Close MK40 4EU is all that remains of the former ROC Group Headquarters. The York Group control has been restored to the state it was in at stand down, and English Heritage has opened it as a Museum.


ROC Museum in York (former York UKWMO Group HQ)
York ROC Group HQ
During the period 1960-62 small underground chambers were constructed to protect the observers from blast and fallout. At this time Group and Sector Headquarters had purpose built bunkers constructed. These were usually semi-sunken to afford protection against minor blast damage and increase the fallout protection factor. The picture shows the York Group HQ, now a museum operated by English Heritage. The HQ originally stood in the grounds of Shelley House, a Government building. The external fence around the museum was added when Shelley House was sold off and demolished for a housing development.
A full description of the Group's function can be found in the website menu Group and Sector Function
Typical ROC Monitoring Post
External View of Post
This photograph is typical of the exterior view of a ROC observer post. A 20 ft vertical ladder leads to an underground chamber only 7ft x 16ft x 7ft high. This houses the observers and their instruments and welfare facilities. Conditions were very primitive, as there was no running water, gas or mains electric.
A full description of the Post and its instruments can be found in the website menu ROC Post Instruments

Locations of Group and Sector Headquarters

Map of UKWMO Groups and Sectors
Map of UK
The map and table show how the twenty five Royal Observer Corp (ROC) Group Headquarter covered the UK. Five of the groups shown in bold letters acted as Sector Headquarters too they are shown green coloured dots on the map.
ROC Group & UKWMO Sector Locations
Sector NameGrpCodeLocationOS GridLat/Lon
Metropolitan1MAIMaidstoneTQ75056151.275479, 0.508396
 2HORHorshamTQ17430351.059886, -0.325795
 3OXFOxfordSP55105151.740829, -1.202682
 4COLColchesterTL98524951.887335, 0.822912
 14WINWinchesterSU49431051.076197, -1.310787
Midland6NORNorwichTG23611252.652889, 1.304433
 7BEDBedfordTL02850352.142067, -0.498842
 8COVCoventrySP45773652.357767, -1.331806
 15LINLincolnTF04672553.239000, -0.433769
 20YORYorkSE58051553.956851, -1.116820
Southern9YEOYeovilST55114950.932714, -2.640723
 10EXEExeterSX97296050.754507, -3.458911
 12BRIBristolST71670251.430669, -2.408887
 13SWACarmarthenSN40519851.854557, -4.318645
 16SHRShrewsburySJ49912652.708531, -2.741573
Western17NWAWrexhamSJ35852853.068130, -2.960850
 21PREPrestonSD53936453.822388, -2.701133
 22CARCarlisleNY38360554.935025, -2.964314
 23DURDurhamNZ27542954.780819, -1.574682
 31BELBelfastIJ26365854.524406, -6.048235
Caledonian24EDIEdinburghNT15973955.951525, -3.347294
 25AYRAyrNS34724455.485867, -4.615725
 28DUNDundeeNO43831456.471445, -2.913399
 29ABEAberdeenNJ90508457.166394, -2.155177
 30INVInvernessNH68345557.480854, -4.198189
The Latitude / Longitude coordinates can be entered into Google Maps or Bing Maps search box, which places a marker on the building or the space it occupied. This method is far more accurate than is possible using the 6-Figure OS Map reference which identifies a spot within 100 metres of the location, therefore can be very misleading.

ROC Monitoring Post Locations

The ROC Posts within each Group Control area are arranged in clusters usually containing three posts, but can be from two to five. One post is designated as the master post. Master posts are numbered from ten with an interval of five (10, 15, 20 etc.) usually starting in the North of the area and working down left to right. The significance of the clusters is explained in accompanying communications sections in the website menu.
Individual posts within the cluster are numbered sequentially in a clockwise direction starting from the master post (10, 11 & 12) (15, 16, 17 & 18.) and are unique only within that group. The image below shows the key points on cluster maps. You may view the maps by using the selection buttons, to print a free map, please use the link at the bottom of this page or the website menu to navigate to the Documentation Library.

Use the buttons below to view Group

These maps represent the situation in March 1989 and do not show the monitoring posts closed as a result of the 1968 spending cuts. This website describes the communications aspects of the ROC, but if you are interested, photographs of every extant post may be found on the Sub-Brit website (
The basemap used on this page is © Copyright Ordnance Survey Data, 2001. The Map is licensed under the Open Government Licence 3.0 Full Licence Text OGL Licence
Creative Commons LicenceThis page is Copyright © RINGBELL.CO.UK, under a Creative Commons License details are explained here.