The Mirage IV was effectively a scaled-up Mirage III, designed to provide French nuclear delivery capability. The prototype first flew in 1959 and was followed by three pre-production and 62 production aircraft. The force was declared operational in March 1968 but in the mid-1970s the role changed from high to low-level attack and the Mirage IVs started to appear in grey/green camouflage. All bomber variants were retired by 1996 but reconnaissance-modified aircraft continued till 2005.