On the outbreak of war in September 1939 the AA defences of Gibraltar had been weak, but the Royal Navy Dockyard and airfield became strategically vital in 1940 after the entry of Italy into the war and the Fall of France. Additional AA guns had been installed, manned by the RA, Royal Navy and Gibraltar Defence Force (GDF). Gibraltar suffered a number of air raids during 1940 by the Italian "Regia Aeronautica" (operating from Sardinia) and from the Vichy French Air Force (from French North Africa) in retaliation for British and Free French attacks on Mers-el-Kebir and Dakar. On other occasions the guns fired at single Italian reconnaissance aircraft, known to the garrison as 'Persistent Percy'.