Westland Zero One is the radio call sign for the Chief Test Pilot of Westland helicopters used by Colin Hague during his fifteen years in that position. During that time he was involved in the development of the Merlin helicopter from its very beginning to its introduction in to service. The memoirs also cover his 17 years service in the Fleet Air Arm as pilot and test pilot at the height of the Cold War, and the now forgotten conflicts in Aden and Borneo.