In October 1939, No. 264 (Madras Presidency) Squadron was reformed at RAF Sutton Bridge to operate the Defiant. Initial training, formal squadron acceptance, and development of tactics began with other aircraft as it received its first Defiants only in early December at Martlesham Heath. In February 1940, the Defiant commenced night fighter training operations; the squadron tested its tactics against British medium bombers – Hampdens and Blenheims – and 264's CO flew against Robert Stanford Tuck in a Spitfire, showing that the Defiant could defend itself by circling and keeping its speed up. It became clear during these trials that the Defiant was suited only to performing bomber-destroyer duties.