The 'Battle of the Heligoland Bight' was fought between the British and German air forces and became the first air battle of World War II to receive a name (18 December 1939).

The battle also inaugurated the 'Defence of the Reich' campaign which, with the 'Battle of the Atlantic', was the longest campaign of the war.

After the UK’s declaration of war on Germany on 3 September 1939, Air Chief Marshal Sir Edgar Ludlow-Hewitt’s RAF Bomber Command began operations against Germany but limited its attacks to those targets that were purely military and therefore offered the minimum of risk to civilians. This limited the command’s efforts primarily to attacks on the Kriegsmarine’s warships in German ports with the object of preventing their use in the 'Battle of the Atlantic'.

Early operations led the RAF to arrive at the conclusion that the fighter was not a serious threat to the modern bomber. These operations were also marked by a lack of co-ordination and minor issues like bad weather and communication problems, which meant none of the operations was very intense. The RAF implemented changes to ensure more aircraft could be launched more rapidly to compensate for these issues.

On 18 December, RAF Bomber Command launched a force of three squadrons against German major warships anchored in the Wilhelmshaven area. A total of 24 Vickers Wellington twin-engined medium bombers (at the time classified as heavy bombers) took off, but two turned back with engine problems before reaching German airspace. The German reaction was slow, but eventually between 80 and 120 fighters were launched, although only 44 made contact with the British bombers. Of the 22 bombers which reached the target area, the Luftwaffe shot down 12, more than half of the attacking force. The battle exercised a huge influence on each side’s strategy. It led the RAF to abandon daylight missions in favour of night bombing as daytime casualties were too high. By way of contrast, the failure of the raid led the Luftwaffe to believe Germany proper was invulnerable to air attack, a belief which was reinforced by the German success of the 'Battle of France', which meant that opposing air forces were pushed too far away for effective bombing attacks on the German homeland.

The Germans' neglect of their day fighter force had serious strategic consequences in later years. By the time they began organising defences to combat the US Army Air Forces' daylight strategic bombing campaign, they were already engaged in a war of attrition for which they were not prepared. This oversight was one of the contributing factors in the defeat of the Luftwaffe in the 'Defence of the Reich' campaign. The 'Battle of the Heligoland Bight' came to be described as 'amongst the most important actions of the entire war'.

Before the outbreak of war, RAF Bomber Command was committed to the concept that air power could win wars without the need for naval and land fighting, since the 'bomber would always get through'. Tightly flown bomber formations with heavy defensive armament were thought capable of warding off opposing fighters even without fighter escort. The RAF lacked a four-engined bomber with adequate defensive protection and which could carry heavy bomb loads to German targets, so the only possible targets within range of the British twin-engined bombers were those in the German industrial region of the Ruhr.

The Netherlands and Belgium wished to remain neutral and refused to allow the RAF to establish bases from which to operate more deeply into Germany. They also forbade overflying by British bombers to and from Germany. After the outbreak of war, the French refused to allow RAF bombers to bomb German cities from French airfields. The French felt secure behind the 'Ligne Maginot', but their air force did not possess the modern bombers with which to attack the Luftwaffe. Moreover, the French fighter forces were not yet ready for an all-out defensive campaign against the Germans. Therefore it was fear of retaliation that was the primary driver for France’s thinking with regard to air warfare. The only recourse for the RAF was therefore to fly missions directly from the UK, and only ports or coastal cities in northern Germany were within feasible reach. This state of affairs suited the British in general, and the Admiralty in particular.

The most immediate threat to the Allies during the 'Phoney War' period was the U-boat. Some of these latter had been sent to sea before the British declaration of war, and after the declaration of war the U-boats began operations against British ships delivering supplies from North America and many parts of the British commonwealth and empire. U-47 sank the obsolescent battleship Royal Oak anchored in the fleet base at Scapa Flow in the Orkney islands group during October 1939, with the loss of 786 men of her crew. The Admiralty therefore exerted pressure for the RAF to concentrate its efforts on RAF Coastal Command rather than its supposedly strategic bomber force. This was debated within the British establishment well into 1941. In keeping with a request from the USA for the avoidance of bombing of civilian targets, the British formulated the Western Air Plan 7B (WAP 7B), which was focussed on attacks against German warships. The Germans also complied with the US request, albeit only after 18 September 1939, when victory in Poland was assured. German ships were thus legitimate targets and, at sea or in port, were far enough away from civilian areas to avoid unnecessary casualties. WAP 7B revolved around the elimination of Germany’s major warships to prevent their use as supplements to the U-boat fleet.

To fit in with this strategy, the RAF’s initial plans involved raids against German shipping on the basis of aerial reconnaissance. This was attempted on 3 September, when a Bristol Blenheim twin-engined aeroplane on a reconnaissance flight over the North Sea spotted a large naval force in the Schillig Roads off Wilhelmshaven. The aeroplane’s radio failed, so no attack could be launched until after the aeroplane had returned to base: 15 Handley Page Hampden and nine Wellington twin-engined bombers were despatched against the German ships, but the weather was poor and the bombers failed to find any targets.

A similar attempt was made on 4 September, when warships were again spotted, this time off Brunsbüttel, Wilhelmshaven and in the Schillig Roads. Once again, the aeroplane’s radio failed and no attack could be launched until after the aeroplane had returned. A force of 10 Blenheim light bombers from No. 110 Squadron and No. 107 Squadron, along with five more from No. 139 Squadron and eight Wellington bombers of No. 149 Squadron, took off to locate the battle-cruisers Gneisenau and Scharnhorst, and the 'pocket battleship' Admiral Scheer, which some of the aircraft found. No. 149 Squadron was not prepared for war: at least one of the crews nearly took off without a bomb load until the pilot, looking into the bomb bay, noticed that it was empty. On the way to the target, Squadron Leader Paul Harris ordered his gunners to test their weapons: they all failed and the aeroplane was therefore heading into German territory defenceless, but desiring to to have to turn back on his first raid, Harris pressed ahead.

The same targets were attacked, in and around Brunsbüttel, by No. 9 Squadron later in the same day. The results were poor with five Blenheim and two Wellington bombers lost and only minimal damage inflicted on the German warships. Admiral Scheer was hit by three bombs that failed to detonate, while the light cruiser Emden, which was not one of the priority targets but was present, was also damaged by a Blenheim that crashed into her forecastle and killed 11 sailors and injured 30.

Oberstleutnant Carl-August Schumacher’s II/Jagdgeschwader 77 took off from Nordholz air base and intercepted No. 9 Squadron. Three of the German pilots each claimed a victory, and these No. 9 Squadron aircraft were the first RAF aircraft to be shot down by German fighters during the war. Another four Blenheim bombers of No. 107 Squadron were shot down by anti-aircraft fire. The Germans believed their air defences had established an effective defence from Allied attack, the use of the early Freya radar having provided the German fighters with eight minutes of the attacking warplanes' approach.

The delay between the sighting of German warships and the arrival of the bombers was clearly too great, and it was decided instead to carry out reconnaissances in force, with formations of bombers despatched over the North Sea to find and attack German warships. Their orders forbade them from attacking ships in port, infringing neutral airspace or even attacking German warships escorting merchant ships. A patrol on 29 September resulted in five Hampden bombers being shot down by Messerschmitt Bf 109 single-engined fighters of the II/JG 77, but an attack by 24 Wellington bombers of Nos 149, 38 and 115 Squadrons on 3 December was more successful, correctly claiming a German minesweeper sunk, while defensive fire from the Wellingtons' gunners repelled German fighter attacks in which one fighter was destroyed for no British loss. The German ships were the auxiliary gunnery training vessel Brummer and the minesweeper M-1407, both sunk by bombs which passed right through each vessel without detonating. A German report stated the attack was cleverly executed from out of the sun and delivered to avoid the nearby civilian areas.

An armed reconnaissance by 12 Wellington aircraft on 14 December resulted in the loss of five of the aircraft as the formation, flying at very low level because of the low cloud base, was engaged by fighter aircraft and anti-aircraft guns. The RAF believed that none of the lost aircraft had been shot down by fighters and so maintained its faith in the bomber’s defensive capabilities when flown in tight formations. This conclusion was odd given the fact that several of the surviving bombers had damage from small-arms fire. The Luftwaffe claimed five bombers for the loss of one fighter while none of the German Flak units claimed a victory.

The Luftwaffe’s air-defence organisation went through a number of changes in the first months of the war. The defence of the northern German ports and vital strategic targets was given to the local or nearest Luftverteidigungskommando (air-defence command). In this case, the unit responsible for the protection of German warships was the Luftverteidigungskommando Hamburg (Hamburg air-defence command).

The system was impractical. The Luftverteidigungskommando Hamburg controlled air and ground defences but each was geographically incapable of supporting the other. There was no combined-arms synthesis, meaning that the Flak arm did not directly support the German defences and thereby create a single mass defence. Instead, fighter units protecting the coast were held there, with Kriegsmarine Flak units, while the Hamburg air defence artillery was held too far inland. The Luftwaffe fighters and Flak units were located too far apart for effective co-ordination.

Co-ordination was not helped by the poor relations between the commanders-in-chief of the Luftwaffe and Kriegsmarine, Generalfeldmarschall Hermann Göring and Grossadmiral Erich Raeder. Effective operation of the system demanded that both services work together, but was in fact beset by co-operation difficulties. A solution to the problem was twofold. Fighter units defending the North Sea coast were subordinated to Luftgaukommando XI(no. 11 air district command) in Hanover. These fighter units would function as an autonomous fighter command or Jagdfliegerführer (fighter flyer leader). The command of the Jagdfliegerführer was given to Oberstleutnant Carl-August Schumacher, a former commander of the II/Jagdgeschwader 77, who had served in the Imperial German navy during World War I, and it was hoped that his naval background and easy personality would ease any difficulties with naval service co-operation. However, Schumacher and his naval counterpart were of equivalent rank, and thus each lacked authority over the other, which was an arrangement that stifled unity of command.

Schumacher was given a new command, the Stab./Jagdgeschwader 1 (command of fighter wing 1), sometimes known as JG Nord (fighter wing north) or JG 'Schumacher'. In addition to the Bf 109 fighter in its D and models, the force was also equipped with the Messerschmitt Bf 110 twin-engined heavy fighter. The lack of action during the 'Phoney War' meant that these aircraft, usually in demand for offensive use by the Luftflotten (air fleets), were temporarily available for defensive service. The Stab./JG 1 controlled five groups with a combined strength of 80 to 100 aircraft.

For the operation which led to the 'Battle of the Heligoland Bight', the RAF committed Air Vice Marshal J. E. A. Baldwin’s No. 3 Group, This usually comprised Nos 9, 37, 38, 99, 115 and 149 Squadrons together with Nos 214 and 21 Squadrons in reserve. The group was hastily set up for daylight missions, having been intended for night bombing, but the quality of the training was poor and many of the crews had not been given proper tuition in formation flying. Only Nos 9 and 214 Squadrons were able to fly in perfect formation. To improve formation flying and give crews experience of combat conditions, No. 37 Squadron practised mock combats with Supermarine Spitfire single-engined fighters of Air Vice Marshal K. R. Park’s No. 11 Group of Fighter Command from RAF Tangmere. Warnings were given by the Spitfire pilots that they could have decimated the squadron within 10 minutes because of their poor formation flying and lack of fighter escort, but these were ignored.

Squadron Leader Paul Harris of No. 149 Squadron and Wing Commander Richard Kellett were the only experienced combat leaders, but Kellett had not flown with either No. 9 or No. 37 Squadrons as a group and had never had a chance to practise formation flying or bombing with them. Moreover, he had been accorded neither the time nor the opportunity to discuss or formulate a plan for bombing naval targets as a group, as squadrons or even as flights. Nor had he even been able to discuss or pass on any tactical advice about what the formation should do in the event of fighter attack. Thus he was given command of a mixed group of squadrons which were highly inexperienced. For the 18 December mission, 24 Wellington bombers of Nos 9, 37 and 149 Squadrons were given to Kellett.

On the morning of 18 December 1939, The Times newspaper published the story of the 'Battle of the River Plate' and the death of the 'pocket battleship' Admiral Graf Spee, and a few hours later RAF Bomber Command attempted to sink another major warship. In accordance with Operational Order B.60 of 17 December, the targets were German warships either in port or at sea. The RAF bombers were ordered to overfly the Heligoland Bight and the port of Wilhelmshaven, attacking ships but avoiding civilian living quarters, merchant shipping or land itself.

The first Wellington took off from RAF Mildenhall in Suffolk at 09.27 with Kellett at the controls; No. 9 Squadron took off from nearby RAF Honington, formed up over King’s Lynn and started out over the North Sea. No. 37 Squadron took off but missed the rendezvous and caught up with the main formation an hour later over the North Sea. Once over the Wash the British aircraft set a course of 040° true, as far as latitude 55° N. The plan was to avoid heavy anti-aircraft artillery concentrations on the Frisian islands group. As the bombers left England the cloud broke and they found themselves without cover in a bright crystal clear sky. Tow of the aircraft turned back, one as a result of engine trouble, the other as escort for the troubled bomber. The remaining bombers flew to the north past the Frisian islands group and then turned due south, continuing their mission in perfect visibility which made it easy to be spotted by German aircraft.

Reaching the German/Danish border, the bombers turned south. The formation headed towards Schleswig-Holstein and then planned to turn due west toward Wilhelmshaven. The move was designed to launch the attack from the east, through the target area’s supposed 'back door'. The plan worked, as the bombers arrived without being intercepted, but the southward part of their track had given the Germans a one-hour warning, as the 'Freya' radar had picked up the bombers 32 miles (50 km) off the coast. As the bombers passed down the coast, anti-aircraft artillery fire from ships and harbour defences was noted. In the target area the bombers also came under heavy anti-aircraft artillery fire from Bremerhaven and Wilhelmshaven, and ships near Schillig Roads also opened fire. The bombers replied with their machine guns in an effort to throw off the gunners' aim. German fire was at the correct altitude but the shells detonated behind the bombers. Soon after this, the formation was over Wilhelmshaven harbour, with Gneisenau and Scharnhorst at anchor below them. The ships were close to the shore and Kellett chose not to risk dropping bombs to avoid civilian casualties. Kellett had been ordered to attack at a minimum altitude of about 10,000 ft (3050 m). The British believed that the greatest danger would come from anti-aircraft fire rather than fighters, as this had by then become part of RAF operational doctrine.

Poor Luftwaffe administration meant that the German defence took time to get the information from their radar sites. Major Harry von Bülow-Bothkamp, commander of the II/JG 77 stated that it was the naval 'Freya' rather than Luftwaffe early warning sites that gave the alert. This was the reason that the bombers made landfall without interception, and the first air engagement occurred an hour after the Luftwaffe 'Freya' made its initial report.

As Kellett was taking off, Schumacher was dismissing any idea that the British would attempt a bombing raid in clear weather. On the island of Wangerooge, an officer was demonstrating the 'Freya' to a visiting naval officer, with the 2/ZG 76 as the 'target'. After some demonstration, the officer swung the set to the north, pointing to the Heligoland Bight. As soon as he did so he picked up an echo, and immediately telephoned Schumacher’s Geschwader at Jever. He was told, however, that the naval radar reported nothing and that it was ridiculous to think the British would attack in such clear skies. The radar officer spoke to von Bülow-Bothkamp, but the latter was dismissive. About 20 minutes later, naval 'Freya' radars also picked up the formation, but still no fighters were scrambled. German radar was just as efficient as its British counterpart, but the problem lay in wholly inadequate communication. The British had combined their radar with an efficient fighter-control system, but the Luftwaffe and Kriegsmarine had poor communication and their areas of responsibility overlapped, creating confusion over who was responsible. Added to this was the German disbelief that RAF Bomber Command would expose itself on a day when conditions favoured the fighter. Only when observers on the ground confirmed that the formation existed were fighters scrambled. The observers described a formation of 44 British aircraft, twice its actual strength.

Kellett’s force approached from the east over the Jade river estuary and on course toward Wilhelmshaven. At 13.10, the RAF formation flew over the mud flats to the west of Cuxhaven and Wesermünde and came under fire from three Flak positions. As Kellett turned westward toward the Jade river estuary and over Wilhelmshaven, another five Flak sites opened fire, while Scharnhorst, Gneisenau and all the other warships in the harbour opened fire in support. In the distance, at Schillig Point, the bombers could see German fighters taking off from a camouflaged airstrip. In a quick briefing, the commander of JG 1 had told his pilots to make a beam attack as it was a blind spot for the Wellington. A stern attack was dangerous, as the British tail gunners could then target an attacking fighter with a co-ordinated and concentrated cone of fire. One weakness also noted by the Germans was that early models of the Wellington lacked self-sealing fuel tanks. This meant if the German fighters hit the wings, the bomber would probably catch fire.

Unworried by the Luftwaffe, No. 149 Squadron was the only unit to drop bombs on the ships in Wilhelmshaven harbour. Six 500-lb (227-kg) bombs fell, but the results were unknown. It was all the RAF had to show for its first major raid on a German target. As the bombers emerged from the anti-aircraft barrage, their formation was disorganised. Kellett’s and Harris’s formations were intact, but Squadron Leader Guthrie was ahead of his No. 9 Squadron, and No. 37 Squadron at the rear was straggling. Its commander, Squadron Leader Hue-Williams, was struggling to catch up with the main formation and was forging ahead of his formation without keeping it together. Other members of Hue-Williams’s squadron increased their speed to keep up with their leader.

Oberleutnant Johannes Steinhoff, flying with Bf 109D fighters of the 10(Nacht)./JG 26 lifted off escorted by a Rotte (pair) from the II/JG 77. At 13.30, they attacked one British group after the anti-aircraft fire had lifted. The Bf 109 fighters claimed seven bombers, with Steinhoff claiming two. At 13.40, a Rotte of Bf 110 heavy fighters from ZG 76, led by Hauptmann Wolfgang Falck, claimed four bombers. Falck’s own aeroplane was severely damaged, forcing him to disengage, but he managed to glide back to base and make a 'dead-stick' landing. Unteroffizier Fresia also made two claims. Harris came under attack from a Bf 109 piloted by Oberleutnant Johann Fuhrmann, who failed to hit the bomber in beam attacks. He then tried a stern attack, against earlier advice, only to be shot down. Fuhrmann managed to land in the sea a few hundred yards from the island of Spiekeroog. Witnesses on the beach saw Fuhrmann attempt to swim to shore, but he drowned. During the battle a Bf 110 piloted by Oberleutnant Gordon Gollob shot down and killed Guthrie of No. 9 Squadron. Hue-Williams of No. 37 Squadron was also shot down, possibly by Hauptmann Reinecke. Soon afterwards, the Germans suffered a casualty when Leutnant Roman Stiegler crashed into the sea while in pursuit of Flying Officer Lemon and was killed. At the same time, the Jagdgruppe 101 claimed two more bombers. Bf 110 fighters from ZG 76 had also attacked the bombers, claiming five more.

Among the German claimants was Helmut Lent, who was credited with two victories. After landing at Jever from a patrol, Lent took off to intercept and engaged a Wellington, killing most of the crew. The Wellington was pouring black smoke and Lent broke off believing it about to crash. Lent then pursued another Wellington, which crashed just off the coast of Borkum. Lent’s third claim was not granted: he attacked and shot down a Wellington, but because the aeroplane had already been badly damaged and judged to be about to crash, Lent was refused the victory and Schumacher, the Stab./JG 1's Geschwaderkommodore, was given the credit. Schumacher also shot down another Wellington close to Borkum. At 13.45, the German fighters, which were at the limit of their endurance, returned to base, and by 14.05, the surviving part of the British bomber formation was beyond interception range.

The German fighter crews claimed 38 bombers shot down, against actual RAF losses of 12 aircraft. The gunners in the British bombers claimed 12 German fighters shot down and another 12 severely damaged, while the actual German casualties were three Bf 109 fighters destroyed, two severely damaged and two Bf 110 heavy fighters severely damaged. Thus there was severe overclaiming by each side. Seven Bf 110 and one Bf 109 fighters suffered light damage. Fuhrmann and Stiegler were the only pilots to die in this action. One Bf 109 of Jagdgruppe 101 was written off. The British aircrews also claimed they had been engaged by between 60 and 80 fighters engaging over the Heligoland Bight.

The Luftwaffe insisted that 44 bombers had been in the air, a figure later increased by the Oberkommando der Luftwaffe to 52. Some hours later these claims were reduced to 34 but months later the various reports were analysed and reduced to 27 'confirmed' victories. This was still over twice the number that was shot down and five more than the size of the formation. German historians have claimed that official British figures were 'edited' to hide losses, but careful examination of the records reveals no deception.

The two sides' tactical assessments of the 'Battle of the Heligoland Bight' were radically different. RAF Bomber Command believed the attack was a failure as a result of poor formation flying and leadership, and also came to the conclusion that better beam defensive armament and self-sealing fuel tanks were needed. These tactical considerations might, they believed, still salvage the day-bomber concept. On 22 December, an unsigned No. 3 Group report stated: 'There is every reason to believe that a very close formation of six Wellington aircraft will emerge from a long and heavy attack by [German] fighters with very few if any casualties to its own aircraft. A loose formation is however liable to suffer very heavy casualties under the same conditions.'

On 19 December, Baldwin reported that Guthrie and Hue-Williams were to blame for racing ahead of their formations and breaking up the defensive formation. Baldwin sent his report to Ludlow-Hewitt, Bomber Command’s commander-in-chief, who replied on 23 December and joined Baldwin in condemning the leaders of Nos 9 and 37 Squadrons for abandoning their flights. Hewitt called this action an 'unforgivable crime', although Harris later stated that this was unfair as Guthrie and Hue-Williams were untrained and had never before faced the Germans. Harris also blamed the headquarters of No. 3 Group on the grounds that there had been no planning or liaison between the squadrons. Harris also noted the group operations staff had provided no formation lessons.

In the Operations Notes, Formation Flying, orders specifically stated that the formation was not to stay together, and that each six-aircraft section was to be a self-contained defensive unit, flying at different heights as more than 12 aircraft per formation made it unwieldy and unmanageable by one leader. Even so, the notes also pointed to the importance of holding a formation within the section. If a section leader sought to follow the formation leader to the detriment of his section, the formation would break apart. Bomber formations were built on the idea of mutual protection: if the formation came apart, each bomber would have to fend for itself, which would enable an opponent to pick off the bombers singly. Guthrie and Hue-Williams did not heed this advice; Kellett had followed the notes and lost only one aeroplane. Harris had also kept his formation together and lost no aircraft.

Within a few weeks there began a debate on whether or not to shift air attacks to the cover of darkness, with Hewitt favouring night.

Another issue that was raised by the mission was the lack of useful bomb sights. At the time, the RAF was using the Course Setting Bomb Sight developed in World War I for aircraft flying at much lower speeds against poorly defended targets. At a 22 December meeting, which had already been scheduled, Ludlow-Hewitt noted that use of this sight demanded that the bomber fly a straight path for a relatively long period of time before dropping its bombs, which made it difficult to attack targets of opportunity, as well as making it easier for anti-aircraft gunners to engine targets which were not manoeuvring. Ludlow-Hewitt requested a new design that required a shorter time to settle and would allow manoeuvring throughout the bomb run. This requirement led to the Mk XIV bomb sight, which became standard in 1942.

At the tactical level, the Germans noted lessons and weaknesses of which they were already aware, particularly the nose and tail turrets of the Wellington were incapable of giving adequate cover against beam attacks. They also noted that the bombers' rigid formation flying had favoured the fighters, allowing them to choose the position and angle of attack. The German report also regarded the attempt by the RAF to attack in clear conditions and perfect visibility at altitudes of 10,050 to 16,405 ft (3000 to 4000 m) as 'criminal folly'. Schumacher stated that anti-aircraft fire proved effective at breaking up formations and damaging bombers, which provided better opportunities for the fighter pilots.

After the 'Weiss' (i) campaign in Poland, the Oberkommando des Heeres’s staff analysis had been rigorous in its analysis of that battle. The Oberkommando des Heeres had assessed the problems of leadership, tactics, and command and control to improve effectiveness. It appears that Schumacher’s fighter units did not do the same and were too busy congratulating themselves on their success. There is little evidence that after the 'Battle of the Heligoland Bight', the Luftwaffe took anything like the army’s approach to assessing the implications of the Polish campaign following their own victory over the Heligoland Bight. The historian of the Luftwaffe general staff noted that the victory was exploited only for propaganda, despite the operational problems and warnings the battle had flagged for attacker and defender.

The progress of the war from September 1939 to the summer of 1941, with a few exceptions, seemed to validate the Luftwaffe’s pre-war focus on the offensive use of its fighter arm. The success of the Luftwaffe in the 'Campaign for Norway' and the battles of the Netherlands, Belgium, France, Yugoslavia and Greece had vindicated the concept. The Luftwaffe had defended German airspace by driving opponents' air power away from Germany’s borders and defeating opponents on the latter’s own skies. The occupation of their opponents' territory denied Germany’s enemies the bases from which to attack German targets by air, and the German daylight defences were rarely tested during this time. This run of events and the knowledge that the RAF was capable only of short penetrations over France in daylight led the Luftwaffe to believe Germany was invulnerable to attack. To maintain the offensive on the front line, bomber production dominated the air industry while the production of fighters was given less priority.

By the time Germany declared war on the USA on 11 December 1941, the failure of the 'Barbarossa' invasion of the USSR meant the Luftwaffe’s method of concentrating all its resources on the front line was failing. The RAF began its campaign of night bombing early in 1940 and by mid-August 1942, the US Army Air Forces had entered the air war in force. Even so, the Oberkommando der Luftwaffe continued to resist reinforcing German airspace and thereby weakening its front-line strength. It was only in May 1942, when the Luftwaffe faced the USAAF for the first time in daylight engagements and the start of the US 8^th Army Air Force’s bombing raids on occupied Europe, that the danger of Allied strategic bombing by day started to give the Oberkommando der Luftwaffe cause for concern. Even by the end of 1942, the measures taken to strengthen daylight anti-aircraft defences remained piecemeal and counterproductive. Generaloberst Hans Jeschonnek, the service’s chief-of-staff, summed up the attitude of the Oberkommando der Luftwaffe when he stated that the latter could deal with the Western Allies' daylight raids with 'one fighter wing'. The events of 1943/44 would prove how far in error this assumption was. Generalleutnant Adolf Galland, the inspector general of the fighter arm and a notable ace, gave lack of organisation and of planning for air defence as one of the greatest mistakes made by the Luftwaffe during the war.