UNITED KINGDOM WARNING AND MONITORING ORGANIZATION

The wartime Royal Observer Corps organization was stood down in May 1945 but increased international tension led to its recommissioning in 1947 with a similar ground observation, aircraft spotting and reporting role
The function of the ROC grew in importance through the early 1950s as it became increasingly integrated with the ROTOR radar system.

Towards the end of the decade, however, its emphasis had changed from aircraft reporting to Fallout Warning and its name changed to UKWMO. Between 1956 and 1962 1,559 underground, four-man observation posts, spread across Britain on an 8-mile grid, were constructed which reported fallout and bomb-blast information to 28 Group Headquarters.

Existing wartime Group Headquarters buildings were replaced between 1959 and 1965 by new, two-level bomb and radiation-proof bunkers,built to two standard designs; semi-underground bunkers in the more vulnerable areas and massively constructed surface blockhouses in those less vulnerable. Group HQs reported to Sector HQs, which in turn reported to the Air Defence Operations Centre, NORAD, military HQs, NATO HQs and local authority emergency centres.

Financial stringencies led to the closure of 686 underground observation posts in 1968 but the system remained in operation at a reduced scale until 1992

ABOVE LEFT: underground observation post at Clutton in Somerset ten years after closure

LEFT: Typical interior view of underground post

BELOW RIGHT: Observation post in Bradford on Avon, Wiltshire, in the early 1960s

ABOVE: Typical semi-underground 'Pagoda' style Group Control bunker. This example, now demolished, was at Bedford

BELOW: Surface blockhouse pattern Group Control at Ayr, Scotland

RIGHT: Interior view of the operations well of the Carmarthen UKWMO Group Control bunker

BELOW: New powerhouse extension attached to the semi-underground National UKWMO Headquarters bunker at Longley Lane, Preston in Lancashire