In the summer of 1940, roughly 3,000 RAF fighter pilots stood between Nazi Germany and the conquest of Britain. Against them, the Luftwaffe fielded over 2,600 aircraft and some of the most experienced combat aviators in the world. For four months — from July to October 1940 — the outcome of the Second World War, and arguably the fate of Western civilisation, was decided every day in the skies over southern England. It was the first major military campaign fought entirely in the air. And it was decided by a margin that, looked at afterwards, was extraordinarily thin.

Winston Churchill, who understood both the stakes and the drama of what was happening above him, found the words that fixed the battle in history: "Never in the field of human conflict was so much owed by so many to so few." He said it on August 20, 1940, when the battle was still being fought and its outcome was uncertain. The pilots who heard it reportedly found it slightly embarrassing. They were too tired to be moved by speeches.

The Machines

The RAF's principal fighter was the Hawker Hurricane — a rugged, highly manoeuvrable biplane-era design updated with a modern Merlin engine. It was slower than the Spitfire and the Messerschmitt Bf 109, but it was stable, easy to repair, and devastatingly effective against German bombers. Two-thirds of all German aircraft destroyed during the Battle of Britain were shot down by Hurricanes.

The Supermarine Spitfire was the aircraft that became the symbol of the battle — sleek, fast, and supremely agile, with an elliptical wing that generated exceptional lift at high speeds. In a turning fight, an experienced Spitfire pilot could outmanoeuvre almost anything. The Bf 109, its primary opponent, was roughly equivalent in performance, with a fuel-injected engine that gave it an advantage in negative-g manoeuvres. RAF pilots in early Hurricanes and Spitfires had carburetted engines that cut out when pushed over into a dive; the famous German tactic of "bunting" — pushing down sharply — exploited exactly this weakness until British engineers hastily modified the carburettors mid-battle.

The Numbers That Nearly Failed

At its peak in August 1940, Fighter Command was losing pilots faster than it could replace them. Not aircraft — the factories were producing Spitfires and Hurricanes faster than they were being destroyed. Pilots were the bottleneck. Training a qualified fighter pilot took months. The loss rate meant that some replacements arrived at squadrons with fewer than ten hours on type. The average survival time for a new pilot in August 1940 was less than a week.

The pilots who held the line were international: British, of course, but also Polish, Czech, Canadian, Australian, New Zealander, South African, Rhodesian, Belgian, French, and American volunteers. The Poles — some of the most experienced combat pilots in Europe, having fought in the September 1939 campaign — were initially viewed with scepticism by the RAF. Within weeks, 303 Squadron's Polish pilots had the highest kill rate of any squadron in Fighter Command. "They are brilliant fighters," said a British liaison officer, "but quite mad."

The Decision That Saved Britain

By early September 1940, the Luftwaffe was close to destroying Fighter Command's ground infrastructure — the radar stations, sector control rooms, and forward airfields that made the RAF's defence system work. A few more weeks of the same targeting, and the RAF might have been unable to respond effectively to an invasion fleet.

Then, on September 7, the Luftwaffe switched its attacks from airfields to London. The reason was partly strategic — Hitler wanted to break British civilian morale — and partly personal: the RAF had bombed Berlin, and Hitler was furious. The shift gave Fighter Command time to repair its infrastructure and recover its strength. It also provoked the RAF into a massive counterattack on September 15 — Battle of Britain Day — in which Luftwaffe losses were so severe that the invasion plans were indefinitely postponed.

The battle was won. Three thousand pilots, a handful of radar stations, and one catastrophically bad German decision had held the line. The invasion never came. The war continued for another five years — but from that point forward, Britain was a base from which the liberation of Europe could eventually be launched. The few had, in fact, saved the many.

Sources: Richard Overy, The Battle of Britain (2000); Stephen Bungay, The Most Dangerous Enemy (2000); Wikipedia, "Battle of Britain"; Imperial War Museum