At the London air show of February 1913 the first-ever armed aeroplane, the EFB-1 "Destroyer", a two-seat biplane, was unveiled by Vickers, Ltd. The designers seemed to fully understand the significance of their new aircraft.
From the event program: "This design makes it possible for the biplane to be used as a machine for offence purposes. On the machine that will appear at the show, it will be seen that Messrs. Vickers have mounted a Maxim [machine] gun, which can be swiveled through an angle of 30 degrees. . .arranged in the cockpit at the centre of gravity of the machine, will be stored 1,500 rounds of ammunition."
The aircraft was the developmental prototype of the Vickers FB.5 "Gunbus", which was deployed on the Western Front with 11 Squadron in July 1915.