The Battle of Britain was a prolonged campaign of aerial warfare which was waged on the very skies of the British Isles, and includes the strategic bombing campaign known as "The Blitz". It began on the 14th of July, coinciding with Bastille Day, and was publicly announced in Paris as a show of French national strength, a desperately needed morale boost following its disastrous defeat during Guderian's Counteroffensive. On the morning of that fateful day, Britain's "CHAIN HOME" radar system picked up hundreds of radar signatures over France, bearing towards Britain, and immediately contacted the "Dowding" ground-intercept system. The element of surprise was lost, and RAF fighter squadrons scrambled to intercept. Despite their fierce resistance, most of the first-wave defenders were killed over England.
French heavy bombers squadrons poured hell over British cities using explosive and incendiary bombs, while dive and light bombers attacked strategic targets such as airfields, dockyards, British Army bases and factories. Many historical neighbourhoods, particularly in London, were reduced to rubble. The strategic objective of this bombing campaign was to demolish Britain's spirit, force them to stop arms exports towards Germany, and perhaps, force them to stay out of the war in Europe at gunpoint. In this aspect, the Blitz, as it would be baptised by the British press, was a complete failure. The civilian population of Great Britain was staunchly defiant and refused to yield, while its civil defense did everything in its power to save as many lives as possible. So too did the government ignore every French demand for surrender. On the 20th of July, 1940, Britain officially joined the Kaiserliche Eisenpakt and declared war on France.
The Republican Air Force itself was forced to retreat towards pre-built secondary airfields. Once reorganised, they gave France the battle it wanted, often outnumbered, but never tactically outmanoeuvered, thanks to the "CHAIN HOME" radio system, which told them exactly when the French took off and where they were headed. The French Red Air Force, on the other hand, had no idea what this system was and how it worked.
Fighting over the skies of Britain continued for several months. In the beginning, French bombing raids numbered in the hundreds of aircraft, but little by little, they were attrited into no more than a dozen aircraft per attack, and often at night. British fighter pilots had proven the quality of their training and the bravery of their spirit. Another important factor for Britain's victory in the Battle of Britain was their definitive technical superiority: while French aircraft were technologically impressive, and more numerous to boot, British designs such as the Supermarine Spitfire Mk. I and the Hawker Hurricane were marvels of aeronautical engineering. They were built to fight, and fight they did.
France's aerial forces were so terribly mauled by the Battle of Britain that the Comintern would never again hold total air superiority against the Allies, though the Soviets still held an edge in the East. Despite this impressive victory, Great Britain was now deeply committed to the war, and now had to content with both the Battle of the Atlantic and the Battle of the Trenches.