In 1939 Boulton & Paul built a twin-engine all-metal biplane under a contract awarded by Imperial Airways. The airline had a requirement for a mailplane capable of carrying a 1,000 lb (454 kg) payload over a 1,000 mile (1609 km) range at reasonable speed, and the company considered its Boulton & Paul P.64 Mailplane to be the answer. Unfortunately it was both expensive and unsatisfactory. First flown at the company's airfield at Mousehold, Norwich, in March 1933, it lasted barely seven months before being destroyed in an unexplained fatal crash during trials at Martlesham Heath in October.
Development of the basic layout was continued, and the resulting Boulton & Paul P.71A was lighter, slimmer and longer. In place of the 555 hp (414 kW) Bristol Pegasus engines of the P.64, the P.71A had 490 hp (365 kW) Armstrong Siddeley Jaguar VIAs, and two aircraft were delivered to Imperial Airways at Croydon in February 1935.
By then, the airline had lost interest in the mail-carrying possibilities and the two aircraft, named 'Boadicea' and 'Britomart', were converted for passenger carrying with 13 seats. As VIP transports they had seven seats, which were easily removable if the aircraft were required for use as light freighters.
The P.71As were both lost within 19 months of delivery. The first of them was damaged beyond repair in
a landing accident at Brussels in October 1935; the second disappeared over the English Channel in September 1936.