Handley Page ultimately designed two largely similar aircraft, designated "H.P.42" and "H.P.45" respectively, to meet different requirements: The H.P.42 was meant to serve Imperial Airways' long-range Eastern routes, while the H.P.45 had been configured to serve their shorter routes across Europe. Imperial Airways, having been suitably impressed by Handley Page's submissions, decided to order four of each variant for its passenger fleet. In Imperial Airways service, the H.P.42 was commonly referred to as the "H.P.42E" (E for "Eastern" routes – India and South Africa), while the H.P.45 was the "H.P.42W" (W for "Western" i.e. European routes). The H.P.42 and H.P.45 designations were internally assigned by Handley Page, thus the HP.45 identifier was not commonly used during the flying lives of the aircraft.