Battle of Britain

Following the evacuation of Allied forces from Dunkirk and the collapse of France in June 1940, the United Kingdom faced Nazi Germany alone in Western Europe. On 16 July 1940, Adolf Hitler issued Directive No. 16, ordering preparations for Operation Sea Lion, an amphibious invasion across the English Channel. The execution of the landing depended entirely upon the Luftwaffe eliminating the Royal Air Force to prevent naval and air interference with landing barges. Air Chief Marshal Sir Hugh Dowding, head of RAF Fighter Command, had husbanded his frontline fighter squadrons during the Battle of France specifically to preserve the aerial defence of the home islands.

The campaign opened on 10 July 1940 with German air attacks against merchant convoys and southern coastal ports, including Dover, Plymouth, and Portsmouth. Reichsminister Hermann Göring directed Luftflotte 2, based in the Low Countries and northern France, and Luftflotte 3, based in Normandy, to lure British fighters into attritional daylight engagements over the Channel. Dowding and Air Vice-Marshal Keith Park, commanding No. 11 Group in southeastern England, declined to commit massed fighter formations over water, scrambling only small numbers of Hawker Hurricanes and Supermarine Spitfires. Britain's integrated air defence network—linking Chain Home radar stations, the Observer Corps, and sector operations rooms—provided early warning and tactical direction that largely nullified German surprise.

On 13 August, the Luftwaffe launched Adlerangriff (Eagle Attack), shifting priority to the systematic destruction of RAF Fighter Command on the ground and in the air. Over the following three weeks, German bombers struck forward radar masts, coastal landing grounds, and inland sector airfields, notably Biggin Hill, Kenley, and Manston. On 18 August, known as the Hardest Day, both air forces sustained severe attrition; excessive losses among Junkers Ju 87 Stuka dive-bombers forced their withdrawal from daylight operations. Heavy attacks on No. 11 Group airfields severely strained British runway repair services, infrastructure, and pilot reserves. However, German Messerschmitt Bf 109 fighters operated at the extreme limit of their fuel range over Kent, leaving bombers exposed whenever dogfights dragged on.

In early September, following an accidental German bombing of London and retaliatory British raids on Berlin, Hitler and Göring redirected the air offensive away from RAF airfields toward London and industrial centres. The daylight Blitz began on 7 September. The tactical shift relieved pressure on Park's damaged sector stations, enabling Fighter Command to repair bases and consolidate pilot strength. On 15 September, the Luftwaffe mounted two massive daylight raids against London. No. 11 Group squadrons repeatedly broke up incoming bomber streams, while Air Vice-Marshal Trafford Leigh-Mallory's No. 12 Group deployed multi-squadron formations from Duxford to reinforce the capital. The failure to sweep British fighters from the sky showed that Fighter Command was far from depleted.

On 17 September 1940, Hitler postponed Operation Sea Lion indefinitely. German air strategy shifted through October toward daylight fighter-bomber sweeps and large-scale nocturnal bombing of urban areas. On 31 October, daylight air battles wound down as adverse autumn weather set in, marking the close of the campaign. The Luftwaffe had failed to secure air superiority, leaving British air defence intact and preserving the British Isles as a base for future operations.