|This title may be a bit of hyperbole, but there is no doubt that the famous RAF Operations Room Plotting Clock made a significant contribution to the war effort... especially during the Battle of Britain. During World War II Great Britain was doted with carefully placed radar installations, aircraft observation posts, and special RAF Operations Rooms assigned to control the Royal Air Force's response to incursions by Nazi aircraft.
There were four Group Operations (Ops) Rooms during the Battle of Britain (two others came on line later in the war). These four Group Ops Rooms, and their many subsidiary Sector Ops Rooms, were charged with processing, organizing, and analyzing information received from the radar stations (via the Headquarters Filter and Operations Rooms in Bentley Priory) and other sources (calls from the Observer Corps, Direction Finding Station reports, Balloon Barrage reports, and so on). They were also charged with coordinating the aerial response to incursions by enemy aircraft via their subordinate Sector Operations Groups. An archival photo of the Uxbridge Group Operations Room is shown below left (Original in RAF Museum - Hendon). You can plainly see the special Group Operations Room Plotting Clock on the wall opposite the map table. The more recent image on the right, photographed by Nick Catford, shows the completely restored Ops Room at Uxbridge, with its Ops Room Clock in place.