The Handley Page H.P.42 and H.P.45 were four-engine biplane airliners designed and manufactured by British aviation company Handley Page, based in Radlett, Hertfordshire. It held the distinction of being the largest airliner in regular use in the world upon the type's introduction in 1931. The H.P.42/45 were designed in response to a specification issued during 1928 by British airline Imperial Airways; the two models share considerable similarities, the H.P.42 being optimised towards greater range at the expense of payload while the H.P.45 had these priorities inverted, allowing the latter to carry more passengers over shorter distances. Imperial Airways approved of Handley Page's proposals and ordered four aircraft of the two variants to serve as the new land-based long-distance flagships of its fleet. On 14 November 1930, the prototype, named Hannibal, conducted its maiden flight. Following their introduction into Imperial Airways, they formed the backbone of the airliner's land-based fleet through most of the 1930s and, along with the company's numerous flying boats, have been considered to be icons of their era. A total of eight aircraft were built, four of each type; all were named, with names beginning with the letter "H". Three of the survivors were pressed into Royal Air Force (RAF) service at the outbreak of the Second World War. By the end of 1940, all of the aircraft had been destroyed as a result of several accidents. Development Work on what would become the H.P.42 was initiated in response to a specification released by British airline Imperial Airways in 1928, which sought a large airliner to operate upon its major routes, including its long distance ones to various parts of the globe. British aircraft manufacturer Handley Page, who had already established a pedigree for developing and constructing above-average sized aircraft, saw the Imperial Airways opportunity as quite attractive and thus embarked on producing their own designs to fulfil it. 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