In response to the issuing of Specification G.18/35 by the British Air Ministry, de Havilland decided to design and produce a single prototype of a modified Rapide for undertaking coastal reconnaissance. Trials using the prototype, "K4772", were performed between April and June 1935 at RAF Martlesham Heath and RAF Gosport. However, it ultimately lost out to its rival, the Avro Anson. K4772 was later used by the Royal Aircraft Establishment (RAE) in automatic landing trials before being broken down for spares. Work on a militarised version of the Rapide was not wasted as multiple sales were soon completed with other military customers, the first of which being to the Spanish government in December 1935.