The Vickers Class K, or simply Vickers K, is a British aircraft machine gun; it was designated Vickers GO No. 1 Mk I in British military service, with "GO" standing for "Gas-Operated". Originally developed from the Vickers-Berthier machine gun, its high rate of fire was necessary as aircraft gunners had shorter windows of opportunity to shoot at other aircraft. Eventually phased out of service by the RAF in favor of the Browning M1919, the guns found new life mounted to the raiding vehicles of the Long Range Desert Group and Special Air Service, who liked its higher rate of fire and larger magazine capacity compared to the Bren. Surplus guns were also adopted by the Royal Navy to replace Lewis Guns on light craft.
Later in the war the gun was developed into an infantry portable variant, the Vickers GO No. 2 Mk I. The No. 2 replaced the rear spade-style pistol grip with a stock, added a more traditional pistol grip below the gun, a small wood handguard or Bren carry handle (both existed) in front of that, as well as a bipod and new sights. This variant was primarily intended for second-line units like those protecting RAF airfields, though they also found their way into frontline combat service with various recon and commando units later in the war.
