Introduction: Radar & Ground Defences Evolve
During The Battle of Britain
One of the most important contributory factors to the success of the air defences during the Battle of Britain was the early warning system known as Radio Direction Finding or Radar.
In the 1930s, when the development of a new generation of fast monoplane fighter aircraft promised the possibility of defence against air attack, it was realized that improvements in early-warning techniques would be equally as necessary. As Britain was so close to the Continent, some method was required to warn the defences as quickly as possible of the approach of hostile raiders. Constant aircraft patrols were too expensive to deploy.
The science of the detection and location of aircraft by radio beams made such rapid progress from the first experiments in February 1935 that exactly five years later a chain of coastal radar stations covering the east and south sides of the country was operational. At 10,000 feet, intruders could be detected at ranges of 50 to 120 miles. As ranges for low-flying aircraft were much shorter, a string of Chain Home Low stations to detect aircraft flying at 1,000 feet and below was built after the war began.
The Germans made a concerted attack on radar stations in Kent, Sussex, and the Isle of Wight on 12 August and a few, uncoordinated raids thereafter. Only Ventnor was put out of action for any significant period. Apart from the difficulty in destroying the open, lattice-work structures of the transmitting and receiving masts, the Germans never fully understood the crucial role of radar to the British and, therefore, did not place the highest of priorities on its destruction.
Radar was the eyes of Fighter Command, without which it would have been unable to see incoming raids early enough to have directed defending fighters to intercept. But its effectiveness was greatly enhanced by being only one element of, and integrated into, a sophisticated command and control network which received the raw information of radar plots and rapidly applied it to direct the use of precious resources of pilots and aircraft to the best possible effect.
WAAF Personnel in a Radiolocation Detection Post.
The central roles played in the defence of Britain by the fighter squadrons and radar system were complemented by various ground elements — the Observer Corps, anti-aircraft guns, balloons, and searchlights — which all contributed to the successful defeat of the Luftwaffe
The Observer Corps, a network of civilian volunteers formed in 1925, had a vital role to play. The chain of coastal radar stations was very effective at plotting raids of incoming hostile aircraft, but it was blind once raiders crossed the coast. Inland, the whole responsibility of the accurate tracking of German aircraft rested with the Observer Corps. Enthusiastic, mostly unpaid, and required to be on duty outdoors in all sorts of weather, members were also largely self-taught in the crucial skills of aircraft recognition and height estimation. When the war broke out, there were 30,000 observers and 1,000 observation posts which were manned continuously. Information went first to an Observer Corps Centre and then straight to Group and Sector Operations Rooms. The system worked well when the weather was fine, but not when rain and low cloud were present.
Anti-Aircraft Command was not formed until 1 April 1939 and its late entry on the scene was to handicap it throughout the Battle. At the end of July 1940, it had only a half of the heavy and less than a third of the light anti-aircraft guns considered essential even before the Germans occupied France and the Low Countries. It was desirable to protect aircraft factories, airfields, ports, naval bases and industrial areas, but priority had to be given to the first of these. From 7 September, when the Germans launched their assault on London, many guns had to be switched immediately to its defence. The anti-aircraft forces were integrated with Fighter Command and operational control was in the hands of Air Chief Marshal Dowding who had an excellent working relationship with the head of AA Command, Lieutenant-General Sir Frederick Pile. Despite the problems, guns shot down approximately 300 German aircraft during the Battle.
Searchlights, which were operated with the gun defences, were active against German raids which flew over Britain on most nights from the beginning of June onwards. They were more plentiful than guns, nearly 4,000 being available towards the approved total of 4,128. In daylight they had the important function of reporting air activity to the gun operations rooms.
RAF Balloon Command was formed in November 1938 to operate barrage balloons over the most vulnerable targets. Expansion was rapid so that, by the end of July 1940, 1,466 were in service, 450 of which were required for the defence of London. The main aim of balloons was to force German aircraft to fly higher thereby reducing bombing accuracy and thus bring them within range of heavy anti-aircraft guns. Balloons were particularly effective against dive bombers. [ More information on RAF barrage balloons is here. ] The photo at left shows elephant-shaped barrage balloons being launched into the air at Cardington, England on May 10, 1938 for their first test "flight." The balloons, intended mainly for the protection of London, were launched by the thousands all over Britain as a barrier against attacking Luftwaffe aircraft during the war (© Hulton-Deutsch Collection/CORBIS, Image ID: HU002488).
Typical Observer Corps Post.