Only one Kestrel was built but it was developed into the Miles Master for the RAF and produced in large numbers at the start of the Second World War.

Instructor and pupil sat in tandem under a simple perspex canopy, with the minimum of framing and with extra clear panels in the fuselage sides behind the rear seat.

[1] The Kestrel did not carry the same military load, though there was provision for a single 0.303 in (7.7 mm) Browning machine gun in the starboard wing outboard of the landing gear, and for a camera in the matching port side position.

[1] However, in 1938, the de Havilland Don, that had won the Air Ministry specification T.6/36 contract, proved unsuitable in service, so orders were placed for a production development of the Kestrel called the Miles Master.

The Master I had some noticeable differences from the Kestrel, such as in the shape of the rear fuselage and fin, the rudder and elevator balancing, the cockpit glazing, and the relocation of the radiator from nose to belly, but was otherwise very similar.