In February 1964 deliveries of the Mirage IV to the French Air Force started, with the first French Mirage IV squadron being declared operational on 1 October that year. The Mirage IV bomber force soon consisted of nine squadrons of four aircraft (2 pairs – one aircraft carrying the nuclear bomb, one a buddy-refuelling tanker) each. When fully built up, the force consisted of three wings. These wings were each divided into three bomber squadrons, each equipped with a total of four Mirage IVs, with each deployed at a different base to minimise the potential for an enemy strike to knock out the entire bomber force. These squadrons were: