During the late 1950s, the owner of one such aircraft, Fred Dunkerley, requested that Miles look into converting the type to use jet propulsion for greater performance.

Its owner quickly put it to use as a somewhat unique racing aircraft for the era, a factor which likely aided the Sparrowjet in multiple victories, including the SBAC Challenge Cup on 21 May 1956, and the King's Cup Race on 13 July 1957, the latter in which the aircraft had reported attained a maximum speed of 228 mph (367 km/h).

However, the Sparrowjet was heavily damaged by a hangar fire while being stored at RAF Upton during July 1964, ending its racing career.

During the late 1940s, it was acquired by racing enthusiast Fred Dunkerley who approached Miles to convert the aircraft to harness the recently developed method of jet propulsion as a means of increasing performance.

It was being piloted by Dunkerley when the Sparrowjet won the SBAC Challenge Cup at Yeadon, West Yorkshire on 21 May 1956, having reportedly achieved an average speed of 197.5 mph.

The Sparrowjet was in storage at RAF Upton when it was severely damaged by a hangar fire in July 1964; at the time, it was only partially assembled, with items such as its engines having been removed.

[9] During 2004, the remains of the Sparrowjet were reportedly being rebuilt by a group based in the Bristol area, who were said to be making use of discarded components from the 1950/53 conversion to aid the restoration effort.