Before the war, there was a belief that German bombers had insufficient range to reach Filton; however, the invasion of France by the Nazis in 1940 changed the situation. As war approached, anti-aircraft guns were set up in a field pasture up on Filton Hill, adjacent to Filton Golf Club, to defend the aircraft factories. On 25 September 1940, German aircraft, based in France, raided Filton, causing extensive damage to the aircraft factories, as well as causing a heavy loss of life when several air-raid shelters were hit. Following the heavy German raid in 1940, a squadron of Supermarine Spitfires were based at Filton.