Initial production version, built to Specification 16/36; first contract placed June 3, 1936. First aircraft flown May 14, 1938, with 1,030 hp Merlin II; Merlin III introduced at 175th aircraft. Early aircraft with two-bladed Airscrew Co wooden propeller; three-bladed metal propeller soon standardised - DH two-position, then DH or (few only) Rotol constant speed unit. Entered service August 1938 with No 19 Sqn at Duxford and nine squadrons operational by September 1939, with ten more by mid-1940. Designation Supermarine Spitfire IA adopted retrospectively in 1940 after 30 aircraft designated Supermarine Spitfire IB when fitted with two Hispano 20-mm cannon each in place of four of the machine guns.

Total Mk I production (excluding conversions to prototypes of later marks), 1,519 by Supermarine and 50 by Westland.

• 6 oz/yd2 | 10 oz/ly | 203 g/m2
• 100% cotton
• Set-in rib collar with shoulder-to-shoulder taping
• Double-needle sleeve and bottom hem
• Preshrunk to minimize shrinkage
• Tear away label
• Design Print Area up to 15x17
• Printed In the USA