Development of the Valetta commenced during immediate postwar years as a consequence of Royal Air Force (RAF) interest in a military transport model of the Viking. Amongst the requirements stipulated for the aircraft was the need for it to rapidly alternate between various different roles, including that of a troop transport, air ambulance, freighter, glider tug and paratroop carrier. To accommodate these various roles, many of the aircraft's furnishings were designed to be rapidly removed and replaced by alternative configurations. Further design changes from the Viking included the adoption of more powerful Bristol Hercules 230 radial engines, a reinforced cabin floor and a strengthened undercarriage.