Supermarine Type 300
K5054 : Birth of a Thoroughbred
K5054 was the Air Ministry registration given to the (Vickers) Supermarine Type 300 prototype.
Construction of K5054 began in Dec 1934 and her maiden flight was on 5 march 1936 at Eastleigh_Aerodrome (later Southampton Airport) piloted by Vickers' chief test pilot Joseph "Mutt" Summers.
http://k5054.com/https://en.wikipedia.org/wiki/Supermarine_Spitfire