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 Ulster Constabulary
The chief officer of the Royal Irish Constabulary was its Inspector-General (the last of whom, Sir Thomas J. Smith served from 11 March 1920 until partition in 1922). Between 1922 and 1969 the position of Inspector-General of the RUC was held by five officers, the last being Sir Arthur Young, who was seconded for a year from the City of London Police to implement the Hunt Report. Under Young, the title was changed to Chief Constable in line with the recommendations of the Hunt Report. Young and six others held the job until the RUC was incorporated to the PSNI. The final incumbent, Sir Ronnie Flanagan, became the first Chief Constable of the PSNI.
In 1970, the military-style rankings and insignia were dropped in favour of standard UK police ranks.