Designed by the Handley Page company's Reading, Berkshire, division (formerly the Miles Aircraft Company), the first Handley Page H.P.R.3 Herald prototype (G-AODE) made its maiden flight on 25th August 1955. Looking not unlike an enlarged and modernized Miles Marathon, which had originated from the same stable, the Herald was of high-wing monoplane configuration with four 870 h.p. wing-mounted Alvis Leonides Major radial piston engines. The fuselage was pressurized, the landing gear of retractable tricycle type, and the tail unit of conventional design. Standard accommodation was for 36 passengers, with a maximum of 44.
The Herald had been expected to appeal to operators in Asia, Australia and South America as a feeder-liner suitable for operation from undeveloped airfields. Market research had shown that operators in these areas wanted an aircraft that was simple and easy to maintain, without the complication of turbine engines. An initial production batch of 25 aircraft was started to meet orders totalling 29 aircraft, but none of these was completed with the powerplant that had been planned. Three years of experience with the Vickers Viscount had demonstrated, most effectively, that the 'new-fangled' turboprop engines which powered it were not only extremely reliable, but also most economical in operation.
With potential operators expressing their doubts about the wisdom of holding to their contracts, and with the similarly sized turboprop-powered Fokker F.27 undergoing its development/certification programme, it was decided in May 1957 to develop a Dart-powered version as an alternative. In fact, only the original prototypes were flown with piston engines, and these were converted subsequently to turboprop power, both flying in their revised form during 1958.
The initial production version was the H.P.R.7 Herald Series 100, with accommodation for a maximum of 47 passengers. The Herald Series 200, with the fuselage lengthened by 3 ft 7 in, had seating for
up to 56. By the time that the Handley Page company collapsed in 1970, production had totalled four Series 100 and 36 Series 200 aircraft, plus eight of the Herald Series 400 variant (a military variant of the Series 200) for the Royal Malaysian Air Force. No further examples were built after the liquidation of this once great company.