Group Operations Room

This underground operations bunker served as the nerve centre for 11 Group Fighter Command during the Battle of Britain and other crucial Second World War air operations. Construction began in late 1938 to designs by Bob Creer of the Air Ministry's Directorate of Works and Buildings, and the building was completed in August 1939. The structure is built of reinforced concrete with an internal framework of rolled steel joists.

The bunker is accessed via steps set within an angled passage lined with shuttered concrete. A steel door opens into a lobby fitted with a wire-mesh grille containing a second door, providing additional security screening for visitors. A steep flight of steps, flanked on both walls by fixed power cabling, descends into the bunker. These stairs and others throughout the building are protected where necessary by iron railings cast to Art Deco-inspired patterns. Throughout the bunker are timber doors, brass switch plates and wall-mounted electrical trunking.

The bunker's operation depended entirely on electrical power supply, telecommunications equipment and a secure ventilation system. Plant Rooms X and Y retain their original electrical generating and air filtration equipment. Room Y contains a filtration unit manufactured by Porton Down Experimental Station with casing by Portsmouth Dockyard, indicating the pioneering nature of this installation. An air compression system for ejecting sewage is also present. The Fuse Room retains its complete set of fuse boxes serving ventilation, lighting, teleprinters, General Post Office power and small power circuits. The General Post Office Room preserves its original boxing and telecommunications plant. The Message Centre retains original fittings including Lampson voice tubes.

The operations and plotting room features along one side a raised dais with panelled front for controllers, affording a clear view of the map table and the Slat Board. The original map has been refixed to the plotting table. The Slat Board recorded the state of readiness and other information about fighter squadrons within the Group. The current board is a reconstruction dating from around 1968 of a board system type introduced in October 1940; some of the marked blackboarding from the earlier Tote Board system survives behind it. Information was cross-referred to a colour-coded clock, which remains wall-mounted in its original position to the left of the board. Above and flanking the dais are rooms occupied by senior Royal Air Force and Army personnel, with original glass-fronted screens projecting into the room.

The interior survives in a remarkably intact state, preserving the direct relationship between its internal plan, detailing, fixtures and form to its intended wartime function.

Historical Significance

This underground operations room played a role of fundamental importance in the economic marshalling of air defence which sustained victory in the Battle of Britain and other key Second World War actions. By September 1940, Britain had become the first nation in history to retain its freedom and independence through air power. The Royal Air Force ended the aura of Nazi invincibility that had characterised Blitzkrieg tactics elsewhere in Europe, providing hope to resistance movements in occupied countries. This, amplified through the media, encouraged the pro-British interventionist lobby within the United States and laid groundwork for Anglo-American cooperation and American rearmament that preceded the Japanese attack on Pearl Harbour. The denial of Britain to the Luftwaffe ensured the country's retention for continued resistance to the Axis powers, the invasion of northern Europe in 1944 and the bomber offensive against targets in Germany. It has been argued that without victory in the Battle of Britain, the Soviet army would not have stopped at the Elbe in 1945, with profound consequences for the political geography of Europe in the second half of the 20th century.

Of all sites involved in the Battle of Britain, none have greater resonance in the popular imagination than the sector airfields within the Groups which bore the brunt of the Luftwaffe onslaught and, in Winston Churchill's words, "on whose organisation and combination the whole fighting power of our Air Force at this moment depended". It was 11 Group, commanded by Air Vice Marshal Keith Park from this underground headquarters, which occupied the front line in the battle. Its sector stations at Northolt, North Weald, Biggin Hill, Tangmere, Debden and Hornchurch took some of the most sustained attacks of the battle, especially between 24 August and 6 September when these airfields and aircraft factories became the Luftwaffe's prime targets.

The building bears a direct relationship in terms of its internal plan, detailing, fixtures and form to its intended function. This includes a pioneering system of air filtration, internal communications systems and telecommunications equipment all designed to ensure continuation of operations in a hostile environment—one that anticipates the design of military and civil defence headquarters in the Cold War period. The plotting room, surrounded by operations and control cabins, comprises the strategic heart of the building. It has survived in a remarkably complete state of preservation, very much as Churchill described it on his visit on 15 September 1940, with raised dais for controllers and glass-fronted boxes for senior commanders protruding above the plotting table.

From this room during the Battle of Britain, Air Vice Marshal Keith Park commanded the deployment of squadrons within 11 Group's sector stations. Filtered information was sent from Royal Observer Corps posts and radar stations to Fighter Command headquarters at Bentley Priory, Stanmore, and simultaneously to the Group operations rooms, whose commanders took critical decisions concerning both deployment of anti-aircraft gunfire and fighter sectors under their command. 11 Group's strategic importance also ensured that—in addition to coordinating regular fighter sweeps over the Channel and occupied Europe—this building played a key role in the deployment of fighter squadrons for the evacuation from Dunkirk in May 1940, the ill-fated Dieppe raid of 1942, the invasion of northwest Europe in 1944 and subsequent operations, and the defence of London and the southeast against the V1 rocket menace. It continued to serve as an operations room in the early phase of the Cold War, closing in 1958.

The operational infrastructure was put in place by Sir Hugh Dowding, in command of Fighter Command during the Battle of Britain from March 1936, building on his earlier position on the Air Council as Member for Research and Development. Although historians have drawn attention to production of obsolete aircraft (notoriously exemplified by the Fairey Battle) in order to achieve crude parity with Luftwaffe figures, the early development and sophistication of German radar technology, and the speed and manoeuvrability of the new generation of monoplane fighters designed by Camm, Mitchell and Messerschmitt, there is broad consensus that it was the infrastructure put in place by Dowding that provided the key to the incisive and economic marshalling of fighter squadrons which guaranteed Fighter Command's survival in the Battle of Britain of 1940.

The system saw Chain Home radar stations (the first five of which became operational in 1938, following development work at Bawdsey) and Observer Corps posts linked by telephone and teleprinter to the Filter Room at Fighter Command Headquarters at Bentley Priory, where plots were checked with those of adjacent stations before decisions concerning deployment and attack could be made. In his detailed description of the 11 Group operations bunker at Uxbridge, Churchill wrote: "All the ascendancy of the Hurricanes and Spitfires would have been fruitless but for this system of underground control centres and telegraph cables, which had been devised and built before the war under Dowding's advice and impulse". It could be said that "Dowding controlled the battle from day to day, Park controlled it from hour to hour, and the 11 Group sector controllers from minute to minute".

So successful was this defence system that the Luftwaffe's own defences were realigned on the British model; one of the critical links in the latter's chain is the operations block at Deelen, now protected by the Dutch government. As a consequence of their historical importance, surviving examples of sector operations rooms within 11 Group at Debden and Northolt have been recommended for statutory protection, along with two sector operations blocks on key stations in 12 and 13 Group to the north at Catterick and Duxford. This is the most important of all the fighter operations blocks to have survived, being in a much better state of preservation than the other Group operations headquarters at Watnall in Nottinghamshire (12 Group), Newcastle (13 Group) and Box in Wiltshire (10 Group). The operations and filter rooms at Bentley Priory have been removed and its underground operations block, built during the Second World War, was substantially remodelled in the 1980s.

Royal Air Force Uxbridge's principal function in the inter-war period was the training of recruits, for whom barracks built around an extensive parade ground had been erected in 1928. Close to the operations block is one surviving wing of Building 79 (Sergeants' Mess), which served as an operations room before completion of the bunker, and Building 79 (The Stand-by Set House) which retains original generating plant by Bellis and Morcombe.