On 10 July 1940, the Battle of Britain officially began with concentrated German attacks on shipping in the English Channel. Air fighting and attacks on convoys had already taken place, but 10 July became the recognised starting date of the main campaign.

Britain’s position had changed sharply during the previous two months. German forces had defeated France, Belgium and the Netherlands, while the British Expeditionary Force had withdrawn from Dunkirk. France signed an armistice on 22 June, leaving Britain to continue the war in western Europe without its principal ally.

Germany began preparing for a possible invasion of Britain. Before troops and ships could cross the Channel, the Luftwaffe needed to weaken the Royal Air Force and gain control of the air over southern England and the invasion routes.

The opening phase concentrated on British supply convoys in the Channel, along with ports and naval installations on the south coast. The attacks threatened shipping and drew RAF fighters into combat. This allowed German commanders to test the strength, tactics and response of Fighter Command.

Fighter Command was led by Air Chief Marshal Hugh Dowding. Its defence depended on more than fighter aircraft. Radar stations detected approaching formations, the Observer Corps tracked aircraft after they crossed the coast and control rooms combined the information. Fighter groups and sector stations then directed squadrons towards the raids.

No. 11 Group, commanded by Air Vice-Marshal Keith Park, carried much of the fighting over south-east England. Hurricanes and Spitfires met German bombers and fighters while ground staff repaired, refuelled and returned aircraft to service.

The fighting of 10 July did not settle the campaign. German attacks increased and changed focus during the following weeks. Radar stations, coastal airfields, Fighter Command bases and aircraft factories became targets as the Luftwaffe tried to weaken the British defensive system.

Fighter Command suffered serious losses but remained operational. The Luftwaffe did not destroy it or gain lasting control of British airspace. Without that control, a German invasion fleet would have faced attack from both the RAF and the Royal Navy.

The Battle of Britain continued until 31 October. Germany’s planned invasion, Operation Sea Lion, was postponed and never attempted.