The Supermarine Spitfire, the only British fighter to be manufactured before, during and after the Second World War, was designed as a short-range fighter capable of defending Britain from bomber attackPrice 2002, p. 35. and achieved legendary status fulfilling this role during the Battle of Britain.McKinstry 2007, p. 3. According to fighter ace J.E. "Johnnie" Johnson it was the best conventional defensive fighter of the war.Sims 1972, p. 89.

The fighter evolved into a multi-role aircraft capable of operating in different environments.McKinstry 2007, p. 6. For example, the Spitfire was a pioneer in the role of the unarmed, photo reconnaissance (P.R.) aircraft that relied on high speed and high altitude to avoid detection and attack.McKinstry 2007, p. 261.

Post-war the Spitfire was to continue to serve as a front line fighter and in secondary roles for several air forces well into the 1950s.Price 1991, p. 10. The last offensive sorties made by RAF Spitfires were flown by 60 Squadron Mk XVIIIs over Malaya on 1 January 1951.Glancey 2006, pp. 140–141.

Early RAF service

Phoney War

The first Spitfire I to enter service with the RAF arrived at 19 Squadron, Duxford, on 4 August 1938 and over the next few weeks aircraft were delivered at the rate of one a week to 19 and 66 Squadrons (also based at Duxford). The next to be equipped with Spitfires was 41 Squadron at Catterick, followed by a succession of squadrons stationed at Hornchurch in Essex.Price 2002, pp. 70–72. The public's first sight of the Spitfire in RAF colours was on Empire Air Day, on 20 May 1939, during a display at Duxford in which the pilot "belly-landed" his aircraft, having forgotten to lower his undercarriage and was fined £5 by the Air Ministry. By the outbreak of the Second World War, there were 306 Spitfires in service with the RAF, 71 in reserve and 2,000 on order; 36 had been written off in accidents.Price 2002, p. 73.

On 6 September 1939, in a "friendly-fire" incident known as the Battle of Barking Creek, two 56 Squadron Hawker Hurricanes were shot down by Spitfires of 74 Squadron over the river Medway, in Kent. One of the Hurricane pilots, P/O Montague Leslie Hulton-Harrop, was the first British pilot fatality of the Second World War. As a consequence the development and manufacture of IFF equipment for RAF aircraft became a high priority.

On 16 October 1939, the Spitfire first saw action against the Luftwaffe when three aircraft each from 602 Squadron and 603 Squadron intercepted nine Junkers Ju 88s of 1./KG30, led by Hauptmann Helmuth Pohle, over Rosyth attempting to attack the cruisers HMS Southampton and HMS Edinburgh in the Firth of Forth.Glancey 2006, p. 64. Two Ju 88s were shot down and another heavily damaged.Price 1996, p. 10.Price 1999, p. 35.

Western Europe The first Spitfire operation over Western Europe took place on 13 May 1940, during the Battle of the Netherlands. German airborne forces had been pinned down in the Battle of the Hague by the Dutch Army. RAF Fighter Command sent 66 Squadron Spitfires to escort Defiants from 264 Squadron to support the Dutch. They encountered Junkers Ju 87s from IV(St)./Lehrgeschwader 1 (LG 1), and shot down four of them. They were soon intercepted by Bf 109s from 5 Staffel Jagdgeschwader 26 (JG 26) that shot down five Defiants and one Spitfire for the loss of one Bf 109.Cull 1999, p. 100.

On 23 May 1940, Spitfires of 54 Squadron were the first to shoot down Bf 109s, over Calais Marck airfield, on the coast of northern France; the first of these is usually credited to either Flying Officer Alan Deere who shot down two (according to other sources, one destroyed plus one probable), or Flg. Off. "Johnny" Allen who shot down one.Sims 1972, pp. 108–111.Deere 1974, pp. 48–53.

During this period 67 Spitfires were lost over France, most of them in the attempt to prevent the Luftwaffe from bombing the evacuation beaches at Dunkirk. While the Spitfires of Fighter Command continued to be based in Britain, at the insistence of Air Vice Marshal Hugh Dowding, from late 1939 there were early photo-reconnaissance Spitfires of "No 2 Camouflage Unit" operating from Seclin in France, gathering photo-intelligence of German defences and cities.Price 2002, p. 95. Throughout the Second World War, photo-reconnaissance Spitfires kept up a constant flow of photographic intelligence, in a role far removed from that of short-range interceptor fighter.

Spitfire night fighter

The documentation to specification F.10/35, which was framed around the Spitfire, was headed "Requirements for Single-engine Day and Night Fighter" and stipulated that the aircraft be equipped with "night flying equipment".

In line with these requirements Spitfire Is, IIs, VAs and VBs were fitted with a powerful, retractable landing-light in each wing. Dorsal and ventral identification lights could be operated in Morse code by the pilot using a small morse key in the cockpit. In an attempt to shield the pilot's eyes from the bright exhaust flames many Spitfires were also fitted with rectangular light-alloy "blinkers" secured to light-alloy brackets fixed to the sides of the fuel-tank housing: these could be easily removed.Price 2002, p. 77.

Spitfires were first used as night fighters during the summer of 1940: the most successful night interceptions took place on the night of 18/19 June 1940 when Flt. Lt. "Sailor" Malan of 74 Squadron shot down two Heinkel He 111s of Kampfgeschwader 4,Price 1996, pp. 14–15. while Flg. Off.s John Petre and George Ball of 19 Squadron each shot down one He 111 of KG 4.Price 1996, p. 15. A week later, on the night of 26/27 June, Pilot Officers R. Smith and R. Marples of 616 Squadron shot down another He 111 of KG 4; Flt. Lt. H. MacDonald of 603 Squadron shot down an He 111 of KG 26 and another He 111 of KG 26 was shot down, possibly with the help of A.A guns by Flg. Off.s A. Johnstone of 602 Squadron and J. Haig of 603 Squadron.Price 1996, p. 16.

Although Spitfires continued to be used on night patrols, the Luftwaffe bombers learned to fly well above the altitudes at which they could be effectively picked up by searchlights and the Spitfires were never to achieve the same success.

Battle of Britain

Overall performance

The Battle of Britain (which officially started on 10 July 1940 and ended 31 October)Ramsay 1989, p. 4. was the first major test of both the Spitfire and of Fighter Command. During the Luftwaffe's onslaught important lessons were learned about the Spitfire's capabilities and its drawbacks.Price 1996, pp. 18–39.

The combat performance of the Spitfire was frequently compared with that of the Hawker Hurricane, which was used in greater numbers during the critical stages of 1940. The Hurricane had thick wings and their structure was such that four .303-inch machine-guns were easily installed in each wing, grouped closely together, with 334 rounds per gun. Installing the guns in the Spitfire was more complicated, because it had a thinner wing and the armament and ammunition boxes had to be widely spaced. That dispersion of firepower was a weakness and at least in this respect the Hurricane – which was also a more stable gunnery platform – was better than the Spitfire.Williams and Gustin 2003, p. 93. The pilots who fought over France had learned to get the armourers back at base to harmonise the Browning machine guns, so that their combined fire met their target in one concentrated burst 250 yards ahead of the wings, instead of the official 400 yards.Glancey 2006, p. 65.

In total Hurricanes shot down more Luftwaffe aircraft of all types than the Spitfire, mainly due to the higher proportion of Hurricanes in the air. Seven out of every 10 German aircraft destroyed during the Battle of Britain were shot down by Hurricane pilots. Losses were also higher among the more numerous Hurricane units. Post-war analysis showed that the Spitfire's "kill ratio" was marginally better than the Hurricane's.

The majority of Mk Is and Mk IIs were armed with eight .303 Browning machine guns. Throughout the battle, Luftwaffe aircraft often returned to base with .303 bullet holes, but no critical damage as they had received armour plating in critical areas and self-sealing fuel tanks became common in bombers.Price 2002, p. 72. Several Mark Is of 19 Squadron were fitted with two 20-mm Hispano-Suiza cannon in 1940. This early Hispano installation proved to be unreliable, with the cannon frequently firing just a few rounds or failing to fire at all. After numerous complaints from the pilots of 19 Squadron the cannon armed Spitfires were replaced by conventionally armed aircraft in September 1940.Price 2002, p. 78. Supermarine and BSA, who manufactured the Hispano under licence, continued work on a reliable cannon installation. A number of Mk Is armed with two cannon and four .303 machine-guns entered operations by late 1940; this version was referred to as the Mk IB. The machine-gun-armed Spitfires were retrospectively called the Mk IA.Price 2002, p. 80.

Although the Merlin III engine of Spitfire Is had a power rating of , supplies of 100 octane fuel from the United States started reaching Britain in early 1940.Wood and Dempster 1990, p. 87."Minutes of Oil Policy Committee meetings." National Archives AVIA 10/282, 2 April, 18 May, 7 August 1940. Retrieved: 15 June 2009. This meant that an "emergency boost" of +12 pounds per square inch was available for five minutes, with pilots able to call on at 3,000 rpm at .Harvey-Bailey 1995, p. 155. This boosted the maximum speed by at sea level and at and improved the climbing performance between sea level and full throttle height.Price 1996, p. 19.Morgan and Shacklady 2000, pp. 55–56. The extra boost was not damaging as long as the limitations set forth in the pilot's notes were followed. As a precaution, however, if the pilot had resorted to emergency boost, he had to report this on landing and it had to be noted in the engine log book.Air Ministry 1940, Section 1, para vii "Combat concessions". The extra boost was also available for the Merlin XII fitted to the Spitfire II.Air Ministry 1940/1972 p. 13 "1. Engine Data Merlin XII, para iii "engine limitations".

Between 1 August 1940 and 31 October, Spitfire losses amounted to 208 lost in combat, seven destroyed on the ground, and 42 in flying accidents.Delve 2007, p. 50.

The Bf 109 and combat tactics

At the time, the Luftwaffe's main single-engine, single-seat fighter was the Messerschmitt Bf 109. Some advantages helped the Spitfires win dogfights, most notably manoeuvrability: the Spitfire had a higher rate of turn and a smaller turning circle than the Messerschmitt.Green 1980, p. 70.Spick 1983, p. 59. There are several accounts of Bf 109 pilots being able to outturn Spitfires, mainly because inexperienced pilots did not turn as tightly as was possible through fear of getting into a high-speed stall. Overall, the aircraft were closely matched in performance and the outcome of combat was largely decided by tactics, position and the skill of the opposing pilots.