The rise of Hitler, the collapse of the Disarmament Conference in 1934, and German rearmament, publicly announced in 1935, made the situation in Europe more menacing. German expansionism indeed placed the spotlight on Anglo-French preparedness. In 1938, when, in the Munich crisis, Hitler successfully intimidated Britain and France over the future of Czechoslovakia, the British service chiefs urged caution. Conscious of numerous global commitments, they warned about the dangers of becoming entangled in major military action on the Continent. There was particular concern about the likely impact of the German bombing of civilian targets. The major impact on public morale of German raids on London in World War One seemed a menacing augury. It was believed, in the words of the ex- and future Prime Minister Stanley Baldwin in 1932, that ‘‘the bomber will always get through.’’ Air Commodore L.E.O. Charlton developed these themes in War from the Air: Past- Present-Future (1935), War over England (1936), and The Menace of the Clouds (1937). Anglo-French fears of war with Germany may have been excessive, given the weaknesses of the Nazi regime, including a lack of enthusiasm among the German leaders, but there was a fear of causing a second ‘‘Great War.’’ Furthermore, the military was poorly configured for war with Germany. As the Deputy Chief of the Imperial General Staff noted in May 1939, ‘‘under the plan approved in April 1938, the Field Force was ‘‘to be organized primarily with a view to reinforcing the Middle East . . .The crisis in September 1938. . .focused sharply the fact that, even when the programme was complete, our forces would be inadequate for a major Continental war.’’
Delay in fighting Germany at least permitted investment in improved effectiveness. In response to the threat from German bombers, attention was switched in Britain from building up a bomber force to fighter defense, with the development of the Hawker Hurricane and the Supermarine Spitfire. These planes reflected the transition of fighters from wooden-based biplanes to all-metal cantilever-wing monoplanes with high-performance engines capable of far greater speeds, range, and armament. Alongside early warning radar, they were to be key to resisting the air assault that Germany launched in 1940. There were also improvements in naval readiness in the late 1930s. A large number of carriers, cruisers, and destroyers were laid down, while, after control over the Fleet Air Arm was transferred from the Royal Air Force (RAF) to the Admiralty in 1937, it was greatly expanded. Radar sets were installed in warships from 1938.
In opposing the Munich agreement, Churchill, then a Conservative backbencher, had told the House of Commons on 5 October 1938 that ‘‘the maintenance of peace depends upon the accumulation of deterrents against the aggressor, coupled with a sincere effort to redress grievances.’’ The buildup of British forces did not provide a deterrent to further German action, but it was to help strengthen Britain’s defenses. However, although Britain was allied to France, the Soviet Union was willing to ally with Germany in 1939, while the United States was not interested in becoming committed to action against appeasement. As the United States was the world’s leading industrial power, this gravely weakened the possible response to Fascist aggression. Indeed the lack of Anglo-American cooperation in the 1930s was a major feature in international relations, and one that affected Britain’s options.
The eventual German air assault on Britain in 1940 was to be the product of the collapse of Britain’s military and diplomatic system that year. Britain and France had declared war on Germany on 3 September 1939, in response to its invasion of Poland, whose security they had guaranteed, but the Anglo-French forces were unable to provide any assistance to Poland, not least by attacking German forces on the French frontier. The British forces sent to France in 1939 were small, short of equipment, particularly tanks, transport, artillery, small arms, and ammunition, and poorly trained for conflict with the Germans. Command and control systems were inadequate, and, due to the fiscal situation, there had been no large-scale army maneuvers for several years. The movement of the British force was too late to have any impact on the war in Poland. Churchill, who had become the First Lord of the Admiralty with the outbreak of war, advocated the dispatch of a fleet to the Baltic specially prepared to resist air attack, but this rash idea, which would have exposed the fleet to air attack in confined waters, was thwarted by his naval advisers.
Moreover, in the Battle of Britain of 1940, the German air assault was defeated. This was a key episode both in British military history and in the history of air power. It was the first major check experienced by the Germans, and one that was critical to the survival of Britain as an independent state, for the air attack was designed to prepare the way for Operation Sealion, the planned invasion, particularly by driving British warships from the Channel. British victory reflected both the deficiencies of the numerically superior German air force, and the capabilities and fighting quality of its numerically inferior British opponents. Radar also played an important role within an integrated air defense system. Initial German attacks on the RAF and its airfields, in what was an air-superiority campaign, designed to force the British to commit their fighters and then to destroy them, inflicted heavy blows on the British, especially on pilot numbers. By early September, Fighter Command, under remorseless pressure by larger forces, seemed close to defeat. However, fighting over Britain, the RAF benefited from the support provided by the ground control organization and could more often recover any pilots who survived being shot down. Furthermore, RAF fighting quality, which had been underestimated by the German planners, was seen in the heavy losses inflicted on the Germans, and the Germans did not appreciate the extent to which the RAF was under pressure.
Once the Germans switched in early September 1940 to bomb London and other cities (the Blitz), a strategy designed to put the German air force center-stage by bombing Britain into submission, the pressure on the RAF diminished. German bombers operating near the edge of fighter escort range provided a vulnerable target, which led the Germans to switch to night attack. There is controversy over losses, but one reasonable assessment is that between 10 July and 31 October, the Germans lost 1,733 aircraft in the Battle of Britain, the British 915. Although German deficiencies played an important role in their failure, British fighting quality, determination, and fortitude were crucial in making these deficiencies manifest, and thus in gaining an important defensive victory.