Royal Observer Corps
In 1929 the control of the Observer Corps passed from the county police forces to the Air Ministry, although Chief Constables retained responsibility for personnel and recruitment matters. 1 March 1929 saw the establishment of the new "Headquarters of the Observer Corps" at Hillingdon House, RAF Uxbridge in the west of London, and Air Commodore Edward A D Masterman CB CMG CBE AFC RAF (Rtd) was appointed as the first commandant of the Observer Corps. "Air Cdre" Masterman held this appointment until his retirement on 1 March 1936, and was succeeded by Air Commodore Alfred Warrington-Morris CG CMG OBE AFC RAF (Rtd), who would lead the Observer Corps through the critical period during the Second World War which saw the RAF emerge bruised but victorious following the Battle of Britain of 1940.
Royal Observer Corps
The headquarters of each ROC "Group" operated from a control "Centre", responsible for and controlled between 30 and 40 observation "Posts", each of which would be some 10 km to 20 km from its neighbour. By 1945 there were 40 centres covering Great Britain, controlling in total more than 1,500 posts. (The ROC did not operate in Northern Ireland until 1954).