In the German night-bombing raid on London on 18 June 1940, Blenheims accounted for five German bombers, thus proving that they were better-suited for night fighting. In July, No. 600 Squadron, by then based at RAF Manston, had some of its Mk IFs equipped with AI Mk III radar. With this radar equipment, a Blenheim from the Fighter Interception Unit (FIU) at RAF Ford achieved the first success on the night of 2–3 July 1940, accounting for a Dornier Do 17 bomber. More successes came, and before long the Blenheim proved itself invaluable as a night fighter. Gradually, with the introduction of the Bristol Beaufighter in 1940–1941, the Blenheim was supplanted by its faster, better-armed descendant.