The keystone of the British defence was the complex infrastructure of detection, command, and control that ran the battle. This was the "Dowding System", after its chief architect, Air Chief Marshal Sir H.C.T. "Stuffy" Dowding, and the leader of RAF Fighter Command. Much of the air defence system had been originally set up from 1917 by Major General E B Ashmore. Dowding built upon and modernised many of the features of this system,[118] including the use of two-way radio and the Royal Observer Corps (ROC).[119] However, the core of Dowding's system was implemented by Dowding himself: the use of Radio Direction Finding (RDF, later called radar, for radio detection and ranging)[120] was at his behest, and its use, supplemented by information by the ROC, was crucial to the RAF's ability to efficiently intercept incoming German aircraft.[121] He also insisted on having the radar operators linked via telephone (whose wires were laid deep underground with concrete anti-bomb protection)[122] to an operational centre: this was Fighter Command control at Bentley Priory.[123] During the Battle several Coastal Command and Fleet Air Arm units came under Fighter Command control. The British airspace was divided up into four Groups. Usually the first indications of incoming air raids were received by the Chain Home Radio Direction Finding (RDF) facilities which were located around the coastlines of Great Britain. In most circumstances, RDF could pick up formations ofLuftwaffe aircraft as they organised over their own airfields. Once the raiding aircraft moved inland over England, the formations were also plotted by the Observer Corps. The information from RDF and the Observer Corps were sent through to the main operations room of Fighter Command Headquarters at Bentley Priory. The plots were assessed to determine whether they were "hostile" or "friendly". If hostile, the information was sent to the main "operations room", which was in a large underground bunker. Here the course information of each raid was plotted by WAAFs who received information by a telephone system. Additional intelligence was provided by the "Y" Service radio posts, which monitored enemy radio transmissions, and the "Ultra" decoding centre based at Bletchley Park. Colour coded counters representing each raid were placed on a large table, which had a map of Britain overlaid and squared off with a British Modified Grid. The colour of counter to use for a new sighting was determined by the time of the sighting, the proper colour being indicated by the minute hand of the sector clock. As the plots of the raiding aircraft moved, the counters were pushed across the map by magnetic "rakes". This system enabled the main "Fighter Controller" (usually of squadron leader rank) and Dowding to see quickly where each formation was heading and allowed an estimate to be made of possible targets. The age of the information was readily apparent from the colour of the counter. Because of the simplicity of the system, decisions could be made quickly and easily. Apart from the controller, most of the room and map information was operated by members of the WAAF. Before the war, there was still a great deal of doubt about the ability of women to stand up to battle conditions, with many airwomen employed on front-line RDF stations and aerodromes.[124] Experience during the battle proved that such doubts were unfounded and the contribution of the WAAFs became essential to the RAF in its control and communications systems and in many other duties.[125][126][127] This information was simultaneously sent to the headquarters of each Group (for example, RAF Uxbridge for 11 Group),[128]where it was "filtered" through a filter room (that is, collated, cross-checked and simplified), before being sent through to another operations room, housed in the Battle of Britain Bunker. Because Group had tactical control of the battle the operations room was different in layout from the one at Bentley Priory. The main map on the plotting table represented the Group command area and its associated airfields. Extensive radio and telephone equipment transmitted and received a constant flow of information from the various sector airfields as well as the Observer Corps, AA Command and the navy. The "Duty fighter controller" was (for example in 11 Group) Park's personal representative, whose job was to control how and when each raid would be dealt with. He ordered the squadrons airborne and positioned them as he thought best. Timing was of the essence, because "(e)ach minute of unnecessary delay waiting to make absolutely sure that the raid was coming in meant about 2,000 feet of vital altitude our fighters would not have when they met the enemy." (Wing Commander Lord Willoughby de Broke, Senior Fighter Controller, Uxbridge.) Each Group room had a "tote board" which showed each squadron available to that group. The tote board had a system of lights which enabled the controllers to see the squadron status: Released (not available); Available (airborne in 20 minutes); Readiness (airborne in 5 minutes); Standby (pilots in cockpit, airborne in 2 minutes); Airborne and moving into position; Enemy sighted; Ordered to land; Landed and refuelling/rearming. Next to the tote board, where it could be clearly seen, was a weather board which showed the state of the weather around each airfield. It was the responsibility of the WAAF plotters to continually update the tote and weather boards.[129][130] A vital role was played by the telephone engineers of the GPO "who worked all hours repairing communications, installing completely new facilities in the emergency centres, and keeping the nervous system of Fighter Command functioning..." (Air Commodore Eric Roberts, Commander Middle Wallop Sector in 1940)[131] Despite appearances, the Groups were not mutually supporting; Park, for instance, could only request – not demand – assistance from Brand (who usually co-operated), or from Leigh-Mallory (who often prevaricated). This was because Dowding had never issued standing orders to assist, nor had he created a method to co-ordinate it.[109] There was a further problem in that the aircraft were not assigned equitably between Groups. While the most effective RAF fighter was the Spitfire, 70% of 11 Group aircraft were Hurricanes. "In total, less than a third of Britain's best fighters were operating in the key sector."[132] The Group areas were subdivided into Sectors; each commanding officer was assigned between two and four squadrons. Sector Stations, comprising an aerodrome with a "Sector operations room", were the heart of this organisation, and they were also responsible for operating satellite aerodromes to which squadrons could be dispersed. The operations rooms duplicated those at the Group HQs, although they were on a smaller scale and most were still housed in brick, single-storey, tile-roofed structures above ground, where they were vulnerable to attack. By 1940, most were semi-protected by an earth bank or "blast wall" surrounding them which reached as high as the eaves. Fortunately for Fighter Command, Luftwaffe Intelligence was unaware of the importance of these rooms and most were left alone. The control rooms at Biggin Hill were destroyed by a raid on 31 August, but this was due to a chance bomb hit. Their vulnerability in time of war was appreciated and new airfields built during the expansion programme of the 1930s had new, bombproof Mk II, L-shaped structures. As a further precaution, emergency control rooms were set up in different locations away from the airfields, with small loss in efficiency; RAF Kenley, for example, could use an alternative room housed in a butcher's shop in nearby Caterham. The plotting table was laid out with a map of the sector and its airfields, and the tote and weather boards reflected this more localised information.[130] When ordered by their Group HQ, the sector stations would "scramble" their squadrons into the air. Once airborne, the squadrons would be directed by radio-telephone (R/T) from their sector station. Squadrons could be ordered to patrol airfields or vital targets or be "vectored" to intercept incoming raids. As well as directing the fighter squadrons, Sector stations also controlled the anti-aircraft batteries in their area; an army officer sat beside each fighter controller and directed the gun crews when to open fire and, if RAF aircraft flew into the gun-zones, ordered the guns to cease fire.[133] Though it was the most sophisticated air defence system in the world at that time, the Dowding System had many limitations, including, but not often stressed, its emphatic need for qualified ground maintenance personnel, many of whom had received their training under the Aircraft Apprentice scheme instituted by Hugh Trenchard. RDF (radar) was subject to significant errors and the Observer Corps had difficulties tracking raids at night and in bad weather. R/T (radio telephone) communications with airborne fighters were restricted because the standard radio set used by RAF fighters at the beginning of the battle was the TR9D HF set, which operated over two selectable frequencies in the band 4.3–6.6 Megahertz (MHz);[134] the RAF soon realised that this equipment was limited in the range at which it could receive and transmit radio signals because of its limited power. In addition, the increase in the number of civil, military and foreign HF-band radio transmitters since the adoption of the TR9 meant that the signal often suffered from distortion and interference, making clear communication with the RAF fighters difficult. It was also restricted to a single frequency per squadron, making inter-squadron communication impossible.[131] Finally, the system for tracking RAF fighters, known as HF/DF or "Huff-Duff", restricted sectors to a maximum of four squadrons in the air. The addition of IFF, "Pipsqueak", while a welcome help in identifying RAF aircraft, took up another radio channel. In late September 1940, VHF T/R Type 1133 radios started replacing the TR9s. These had first been fitted to Spitfires of 54 and 66 Squadrons starting in October 1939,[131] but production delays with the improved T/R 1143 set meant the bulk of Spitfires and Hurricanes were not fitted with this equipment until October 1940. The reception was much clearer over a longer range, and controllers and pilots had a wider range of communications channels to choose from.[131][134] It is unclear how much the British intercepts of the Enigma cipher, used for high-security German radio communications, affected the battle. Ultra, the information obtained from Enigma intercepts, gave the highest echelons of the British command a view of German intentions. According to F. W. Winterbotham, who was the senior Air Staff representative in the Secret Intelligence Service,[135] Ultra helped establish the strength and composition of the Luftwaffe's formations, the aims of the commanders[136] and provided early warning of some raids.[137]In early August it was decided that a small unit would be set up at Fighter Command headquarters (Stanmore), which would process the flow of information from Bletchley and provide Dowding only with the most essential Ultra material; thus the Air Ministry did not have to send a continual flow of information to Stanmore, preserving secrecy, and Dowding was not inundated with non-essential information. Keith Park and his controllers were also told about Ultra.[138] In a further attempt to camouflage the existence of Ultra Dowding created a unit called 421 Flight. This unit (which later became 91 Squadron), was equipped with Hurricanes and Spitfires and sent out aircraft to search for and report Luftwaffe formations approaching England.[139] In addition the radio listening service (known as Y Service), monitoring the patterns of Luftwaffe radio traffic, contributed considerably to the early warning of raids. One of the biggest oversights of the entire system was the lack of a proper air-sea rescue organisation. The RAF had started organising a system in 1940 with High Speed Launches (HSLs) based on flying boat bases and at a number of overseas locations, but it was still believed that the amount of cross-Channel traffic meant that there was no need for a rescue service to cover these areas. Downed pilots and aircrew, it was hoped, would be picked up by any boats or ships which happened to be passing by. Otherwise the local life boat would be alerted, assuming someone had seen the pilot going into the water.[140] RAF aircrew were issued with a life jacket, nicknamed the "Mae West" but in 1940 it still required manual inflation, which was almost impossible for someone who was injured or in shock. The waters of the English Channel and Dover Straits are cold, even in the middle of summer, and clothing issued to RAF aircrew did little to insulate them against these freezing conditions. A conference in 1939 had placed air-sea rescue under Coastal Command. Because a number of pilots had been lost at sea during the "Channel Battle", on 22 August, control of RAF rescue launches was passed to the local naval authorities and 12 Lysanders were given to Fighter Command to help look for pilots at sea. In all some 200 pilots and aircrew were lost at sea during the battle. No proper air-sea rescue service was formed until 1941.[101] The weight of the battle fell upon 11 Group. Keith Park's tactics were to dispatch individual squadrons to intercept raids. The intention was to subject incoming bombers to continual attacks by relatively small numbers of fighters and try to break up the tight German formations. Once formations had fallen apart, stragglers could be picked off one by one. Where multiple squadrons reached a raid the procedure was for the slower Hurricanes to tackle the bombers while the more agile Spitfires held up the fighter escort. This ideal was not always achieved, resulting in occasions when Spitfires and Hurricanes reversed roles.[141] Park also issued instructions to his units to engage in frontal attacks against the bombers, which were more vulnerable to such attacks. Again, in the environment of fast moving, three-dimensional air battles, few RAF fighter units were able to attack the bombers from head-on.[141] During the battle, some commanders, notably Leigh-Mallory, proposed squadrons be formed into "Big Wings," consisting of at least three squadrons, to attack the enemy en masse, a method pioneered by Douglas Bader. Proponents of this tactic claimed interceptions in large numbers caused greater enemy losses while reducing their own casualties. Opponents pointed out the big wings would take too long to form up, and the strategy ran a greater risk of fighters being caught on the ground refuelling. The big wing idea also caused pilots to over-claim their kills, due to the confusion of a more intense battle zone. This led to the belief big wings were far more effective than they were.[142] The issue caused intense friction between Park and Leigh-Mallory, as 12 Group was tasked with protecting 11 Group's airfields whilst Park's squadrons intercepted incoming raids. However, the delay in forming up Big Wings meant the formations often did not arrive at all or until after German bombers had hit 11 Group's airfields.[143] Dowding, to highlight the problem of the Big Wing's performance, submitted a report compiled by Park to the Air Ministry on 15 November. In the report, he highlighted that during the period of 11 September – 31 October, the extensive use of the Big Wing had resulted in just 10 interceptions and one German aircraft destroyed, but his report was ignored.[144] Post-war analysis agrees Dowding and Park's approach was best for 11 Group. Dowding's removal from his post in November 1940 has been blamed on this struggle between Park and Leigh-Mallory's daylight strategy. However, the intensive raids and destruction wrought during the Blitz damaged both Dowding and Park in particular, for the failure to produce an effective night-fighter defence system, something for which the influential Leigh-Mallory had long criticised them.[145] Bomber Command and Coastal Command aircraft flew offensive sorties against targets in Germany and France during the battle. After the initial disasters of the war, with Vickers Wellington bombers shot down in large numbers attacking Wilhelmshaven and the slaughter of theFairey Battle squadrons sent to France, it became clear that Bomber Command would have to operate mainly at night to achieve any results without incurring very high losses.[146] From 15 May 1940, a night time bomber campaign was launched against the German oil industry, communications, and forests/crops, mainly in the Ruhr area. As the threat mounted, Bomber Command changed targeting priority on 3 June 1940 to attack the German aircraft industry. On 4 July, the Air Ministry gave Bomber Command orders to attack ports and shipping. By September, the build-up of invasion barges in the Channel ports had become a top priority target.[147] On 7 September, the government issued a warning that the invasion could be expected within the next few days and, that night, Bomber Command attacked the Channel ports and supply dumps. On 13 September, they carried out another large raid on the Channel ports, sinking 80 large barges in the port of Ostend.[148] 84 barges were sunk in Dunkirk after another raid on 17 September and by 19 September, almost 200 barges had been sunk.[147] The loss of these barges may have contributed to Hitler's decision to postpone Operation Sealion indefinitely.[147] The success of these raids was in part because the Germans had few Freya radar stations set up in France, so that air defences of the French harbours were not nearly as good as the air defences over Germany; Bomber Command had directed some 60% of its strength against the Channel ports. The Bristol Blenheim units also raided German-occupied airfields throughout July to December 1940, both during daylight hours and at night. Although most of these raids were unproductive, there were some successes; on 1 August, five out of 12 Blenheims sent to attack Haamstede and Evere (Brussels) were able to bomb, destroying or heavily damaging three Bf 109s of II./JG 27 and apparently killing a Staffelkapitän identified as a Hauptmann Albrecht von Ankum-Frank. Two other 109s were claimed by Blenheim gunners.[149][nb 23]Another successful raid on Haamstede was made by a single Blenheim on 7 August which destroyed one 109 of 4./JG 54, heavily damaged another and caused lighter damage to four more.[150] There were some missions which produced an almost 100% casualty rate amongst the Blenheims; one such operation was mounted on 13 August 1940 against a Luftwaffe airfield nearAalborg in north-eastern Denmark by 12 aircraft of 82 Squadron. One Blenheim returned early (the pilot was later charged and due to appear before a court martial, but was killed on another operation), the other 11, which reached Denmark, were shot down, five by flak and six by Bf 109s. Of the 33 crewmen who took part in the attack, 20 were killed and 13 captured.[151] As well as the bombing operations, Blenheim-equipped units had been formed to carry out long-range strategic reconnaissance missions over Germany and German-occupied territories. In this role, the Blenheims again proved to be too slow and vulnerable against Luftwaffe fighters, and they took constant casualties.[152][page needed] Coastal Command directed its attention towards the protection of British shipping, and the destruction of enemy shipping. As invasion became more likely, it participated in the strikes on French harbours and airfields, laying mines, and mounting numerous reconnaissance missions over the enemy-held coast. In all, some 9,180 sorties were flown by bombers from July to October 1940. Although this was much less than the 80,000 sorties flown by fighters, bomber crews suffered about half the total number of casualties borne by their fighter colleagues. The bomber contribution was, therefore, much more dangerous on a loss-per-sortie comparison.[153] It is a testament to the courage of the men in these bomber, reconnaissance and Coastal Command units that they continued to operate throughout these months with little respite and with little of the publicity accorded to Fighter Command. In his famous 20 August speech about "The Few", praising Fighter Command, Churchill also made a point to mention Bomber Command's contribution, adding that bombers were even then striking back at Germany; this part of the speech is often overlooked.[154][155] The Battle of Britain Chapel in Westminster Abbey lists in a Roll of Honour 718 Bomber Command crew members, and 280 from Coastal Command who were killed between 10 July and 31 October.[156] The Battle can be roughly divided into four phases: The Kanalkampf comprised a series of running fights over convoys in the English Channel and occasional attacks on the convoys by Stuka dive bombers. It was launched partly because Kesselring and Sperrle were not sure about what else to do, and partly because it gave German aircrews some training and a chance to probe the British defences.[95] These battles off the coast tended to favour the Germans, whose bomber escorts massively outnumbered the convoy patrols. The need for constant patrols over the convoys put a severe strain on RAF pilots and machines. It cost fuel and engine hours and exhausted pilots. Eventually, ship losses became so great the British Admiralty cancelled all further convoys through the Channel. However, these early combat encounters provided both sides with experience. They also gave the first indications some aircraft, such as the Defiant and Bf 110, were not up to the intense dog-fighting that would characterise the battle. The main attack upon the RAF's defences was code-named Adlerangriff ("Eagle Attack"). Poor weather delayed Adlertag ("Eagle Day") until 13 August 1940. On 12 August, the first attempt was made to blind the Dowding system, when aircraft from the specialist fighter-bomber unit Erprobungsgruppe 210 attacked four radar stations. Three were briefly taken off the air but were back working within six hours.[157] The raids appeared to show that British radars were difficult to knock out. The failure to mount follow-up attacks allowed the RAF to get the stations back on the air, and the Luftwaffe neglected strikes on the supporting infrastructure, such as phone lines and power stations, which could have rendered the radars useless, even if the towers themselves (which were very difficult to destroy) remained intact.[109] Adlertag opened with a series of attacks, led again by Epro 210,[157] on coastal airfields used as forward landing grounds for the RAF fighters, as well as 'satellite airfields'[nb 24] (includingManston and Hawkinge).[157] As the week drew on, the airfield attacks moved further inland, and repeated raids were made on the radar chain. 15 August was "The Greatest Day" when the Luftwaffe mounted the largest number of sorties of the campaign. Luftflotte 5 attacked the north of England. Believing Fighter Command strength to be concentrated in the south, raiding forces from Denmark and Norway ran into unexpectedly strong resistance. Inadequately escorted by Bf 110s, bombers were shot down in large numbers. North East England was attacked by 65 Heinkel 111s escorted by 34 Messerschmitt 110s, and RAF Great Driffield was attacked by 50 unescorted Junkers 88s. Out of 115 bombers and 35 fighters sent, 16 bombers and 7 fighters were destroyed.[158] As a result of these casualties, Luftflotte 5 did not appear in strength again in the campaign. 18 August, which had the greatest number of casualties to both sides, has been dubbed "The Hardest Day". Following the grinding battles of 18 August, exhaustion and the weather reduced operations for most of a week, allowing the Luftwaffe to review their performance. "The Hardest Day" had sounded the end for the Ju 87 in the campaign.[159] This veteran ofBlitzkrieg was too vulnerable to fighters to operate over Britain, and to preserve the Stuka force, Göring withdrew them from the fighting. This removed the main Luftwaffe precision-bombing weapon and shifted the burden of pinpoint attacks on the already-stretched Erpro 210. The Bf 110 proved too clumsy for dogfighting with single-engined fighters, and its participation was scaled back. It would only be used when range required it or when sufficient single-engined escort could not be provided for the bombers. Göring made yet another fateful decision: to order more bomber escorts at the expense of free-hunting sweeps. To achieve this, the weight of the attack now fell on Luftflotte 2, and the bulk of the Bf 109s in Luftflotte 3 were transferred to Kesselring's command, reinforcing the fighter bases in the Pas-de-Calais. Stripped of its fighters, Luftflotte 3 would concentrate on the night bombing campaign. Göring, expressing disappointment with the fighter performance thus far in the campaign, also made sweeping changes in the command structure of the fighter units, replacing many Geschwaderkommodore with younger, more aggressive pilots like Adolf Galland and Werner Mölders.[160] Finally, Göring stopped the attacks on the radar chain. These were seen as unsuccessful, and neither the Reichsmarschall nor his subordinates realised how vital the Chain Home stations were to the defence. It was known that radar provided some early warning of raids, but the belief among German fighter pilots was that anything bringing up the "Tommies" to fight was to be encouraged. Göring ordered attacks on aircraft factories on 19 August 1940; on 23 August 1940 he ordered that RAF airfields be attacked. That evening an attack was mounted on a tyre factory in Birmingham. Raids on airfields continued through 24 August, and Portsmouth was hit by a major attack. That night, several areas of London were bombed; the East End was set ablaze and bombs landed on central London. Some historians believe that these bombs were dropped accidentally by a group of Heinkel He 111s which had failed to find their target; this account has been contested.[161] In retaliation, the RAF bombed Berlin on the night of 25–26 August, and continued bombing raids on Berlin. Göring's pride was hurt, as he had previously claimed the British would never be able to bomb the city. The attacks enraged Hitler, who ordered retaliatory attacks on London.[162] From 24 August onwards, the battle was a fight between Kesselring's Luftflotte 2 and Park's 11 Group. The Luftwaffe concentrated all their strength on knocking out Fighter Command and made repeated attacks on the airfields. Of the 33 heavy attacks in the following two weeks, 24 were against airfields. The key sector stations were hit repeatedly: Biggin Hill and Hornchurch four times each; Debden and North Weald twice each. Croydon, Gravesend, Rochford, Hawkinge and Manston were also attacked in strength. Coastal Command's Eastchurch was bombed at least seven times because it was believed to be a Fighter Command aerodrome. At times these raids caused some damage to the sector stations, threatening the integrity of the Dowding system. To offset some losses, some 58 Fleet Air Arm fighter pilot volunteers were seconded to RAF squadrons, and a similar number of former Fairey Battle pilots were used. Most replacements from Operational Training Units (OTUs) had as little as nine hours flying time and no gunnery or air-to-air combat training. At this point, themultinational nature of Fighter Command came to the fore. Many squadrons and personnel from the air forces of the Dominions were already attached to the RAF, including top level commanders – Australians, Canadians, New Zealanders, Rhodesians and South Africans. In addition, there were other nationalities represented, including Free French, Belgian and a Jewish pilot from the British mandate of Palestine. They were bolstered by the arrival of fresh Czechoslovak and Polish squadrons. These had been held back by Dowding, who mistakenly thought non-English speaking aircrew would have trouble working within his control system. However, Polish and Czech fliers proved to be especially effective. The pre-war Polish Air Force had lengthy and extensive training, and high standards; with Poland conquered and under brutal German occupation, the pilots of No. 303 (Polish) Squadron, the highest-scoring Allied unit,[163] were strongly motivated. Josef František, a Czech regular airman who had flown from the occupation of his own country to join the Polish and then French air forces before arriving in Britain, flew as a guest of 303 Squadron and was ultimately credited with the highest "RAF score" in the Battle of Britain.[164] The RAF had the advantage of fighting over home territory. Pilots who bailed out of their downed aircraft could be back at their airfields within hours. For Luftwaffe aircrews, a bailout over England meant capture, while parachuting into the English Channel often meant drowning or death from exposure. Morale began to suffer, and Kanalkrankheit ("Channel sickness") – a form of combat fatigue – began to appear among the German pilots. Their replacement problem was even worse than the British. The effect of the German attacks on airfields is not straightforward. Stephen Bungay's research tells us that Dowding, in a letter to Hugh Trenchard[165] accompanying Park's report on the period 8 August – 10 September 1940, states that the Luftwaffe "achieved very little" in the last week of August and the first week of September.[166] The only Sector Station to be shut down operationally was Biggin Hill, and it was non-operational for just two hours. Dowding admitted 11 Group's efficiency was impaired but, despite serious damage to some airfields, only two out of 13 heavily attacked airfields were down for more than a few hours. The German refocus on London was not critical.[166] Air Vice Marshal Peter Dye, head of the RAF Museum, discussed the logistics of the battle in 2000[167] and 2010,[168] dealing specifically with the single-seat fighters. Dye contends that not only was British aircraft production replacing aircraft, but replacement pilots were keeping pace with losses. The number of pilots in RAF Fighter Command increased during July, August and September. The figures indicate the number of pilots available never decreased. From July, 1 200 were available. In 1 August, 1 400 were available. Just over that number were in the field by September. In October the figure was nearly 1,600. By 1 November 1800 were available. Throughout the battle, the RAF had more fighter pilots available than theLuftwaffe.[167][168] Although the RAF's reserves of single seat fighters fell during July, the wastage was made up for by an efficient Civilian Repair Organisation (CRO), which by December had repaired and put back into service some 4,955 aircraft,[169] and by aircraft held at Air Servicing Unit (ASU) airfields.[170] Richard Overy endorses Dye and Bungay. Overy asserts only one airfield was temporarily put out of action and "only" 103 pilots were lost. British fighter production produced 496 new aircraft in July and 467 in August, and another 467 in September (not counting repaired aircraft), covering the losses of August and September. Overy indicates the number of serviceable and total strength returns reveal an increase in fighters from 3 August to 7 September, 1,061 on strength and 708 serviceable to 1,161 on strength and 746 serviceable.[171] Moreover, Overy points out that the number of RAF fighter pilots grew by one-third between June and August 1940. Personnel records show a constant supply of around 1,400 pilots in the crucial weeks of the battle. In the second half of September it reached 1,500. The shortfall of pilots was never above 10 percent. The Germans never had more than between 1,100 and 1,200 pilots, a deficiency of up to one-third. "If Fighter Command were 'the few', the German fighter pilots were fewer".[172] American historian James Corum points out that it was unlikely that the Luftwaffe was ever able to destroy the RAF. If British losses became severe, the RAF could simply withdraw northward and regroup. It could then deploy when and if the Germans launched an invasion. Corum doubts that the Luftwaffe could have defeated the RAF in the limited time available before the weather window closed in October. Corum also argues that the Sea Lion would have failed because of the weaknesses of German sea power.[173] Older history books assert this period was the most dangerous of all. In The Narrow Margin, published in 1961, historians Derek Wood and Derek Dempster believed that the period from 24 August to 6 September represented a real danger. According to them, from 24 August to 6 September 295 fighters had been totally destroyed and 171 badly damaged, against a total output of 269 new and repaired Spitfires and Hurricanes. They assert that 103 pilots were killed or missing and 128 were wounded, which represented a total wastage of 120 pilots per week out of a fighting strength of just fewer than 1,000. They conclude that during August no more than 260 fighter pilots were turned out by OTUs and casualties in the same month were just over 300. A full squadron establishment was 26 pilots whereas the average in August was 16. In their assessment, the RAF was losing the battle.[174] By this point Hitler had becoming impatient with the Luftwaffe. On 14 September, General Hans Jeschonnek, Luftwaffe Chief of Staff, persuaded Hitler for a last chance to defeat the RAF and sought permission to launch attacks on civilian residential areas to cause mass panic. Hitler refused the latter, perhaps unaware of just how much damage had already been done to civilian targets, as he wanted to reserve for himself the right to unleash the terror weapon. Political will was to be broken by the collapse of the material infrastructure, the weapons industry, along with the destruction of stocks of fuel and food. On 16 September, Göring ordered the air fleets to begin the new phase of the battle.[175] Hitler's No. 17 Directive, issued 1 August 1940 on the conduct of war against England specifically prohibited Luftwaffe from conducting terror raids on its own initiative, and reserved the right of ordering terror attacks as means of reprisal for the Führer himself:[176] The Luftwaffe offensive against Britain had included numerous raids on major ports since August, but Hitler had issued a directive London was not to be bombed save on his sole instruction.[178] However, on the afternoon of 15 August,Hauptmann Walter Rubensdörffer leading Erprobungsgruppe 210 mistakenly bombed the Croydon airfield (on the outskirts of London) instead of the intended target, RAF Kenley;[179] this was followed on the night of 23/24 August[148] by the accidental bombing of Harrow, also on the outskirts of London, as well as raids on Aberdeen, Bristol, and South Wales. The focus on attacking airfields had also been accompanied by a sustained bombing campaign which begun on 24 August with the largest raid so far, killing 100 in Portsmouth, and that evening the first night raid on London as described above.[161] On 25 August 1940, 81 bombers of Bomber Command were sent out to raid industrial and commercial targets in Berlin. Clouds prevented accurate identification and the bombs fell across the city, causing some casualties amongst the civilian population as well as damage to residential areas.[180] Continuing RAF raids on Berlin in retaliation led to Hitler withdrawing his directive,[181] and on 3 September Göring planned to bomb London daily, with Kesselring's enthusiastic support, having received reports the average strength of RAF squadrons was down to five or seven fighters out of 12 and their airfields in the area were out of action. Hitler issued a directive on 5 September to attack cities including London.[182][183] In his speech delivered on the 4 September 1940, Hitler threatened to obliterate (ausradieren) British cities if British bombing runs against Germany did not stop. On 7 September, a massive series of raids involving nearly four hundred bombers and more than six hundred fighters targeted docks in the East End of London, day and night. The raids were codenamed Operation Loge. The RAF anticipated attacks on airfields and 11 Group rose to meet them, in greater numbers than the Luftwaffe expected. The first official deployment of 12 Group's Big Wing took twenty minutes to gain formation, missing its intended target, but encountering another formation of bombers while still climbing. They returned, apologetic about their limited success, and blamed the delay on being requested too late.[162][184] Fighter Command had been at its lowest ebb, short of men and machines, and the break from airfield attacks allowed them to recover. 11 Group had considerable success in breaking up daytime raids. 12 Group repeatedly disobeyed orders and failed to meet requests to protect 11 Group airfields, but their experiments with increasingly large Big Wings had some successes. The Luftwaffe began to abandon their morning raids, with attacks on London starting late in the afternoon for 57 consecutive nights of attacks.[185] The most damaging aspect to the Luftwaffe of the change in targets (to London) was the increase in range. The Bf 109 escorts had a limited fuel capacity, and by the time they arrived had only 10 minutes of flying time before they had to turn for home. This left many raids undefended by fighter escorts. On 14 September Hitler chaired a meeting with the OKW staff. Göring was absent in France, as he had decided to direct the decisive part of the battle from there, and left Erhard Milch to deputise for him.[186] At the meeting Hitler raised the question, "Should we call it off altogether?". Hitler had accepted that an invasion with massive air cover was no longer possible. Instead he opted to try to crush British morale, while maintaining the threat of invasion. Hitler concluded this might result in "eight million going mad" (referring to the population of London in 1940), which would "cause a catastrophe" for the British. In those circumstances, Hitler said, "even a small invasion might go a long way". At this point Hitler was against cancelling the invasion as "the cancellation would reach the ears of the enemy and strengthen his resolve".[nb 25][nb 26] On 15 September two massive waves of German attacks were decisively repulsed by the RAF, with every aircraft of 11 Group being used on that day. The total casualties on this critical day were 60 German and 26 RAF aircraft shot down. The German defeat caused Hitler to order, two days later, the postponement of preparations for the invasion of Britain. Henceforth, in the face of mounting losses in men, aircraft and the lack of adequate replacements, theLuftwaffe switched from daylight to nighttime bombing. The air battles on the 15 September became known as the Battle of Britain Day. On 27 September, a Junkers Ju 88 returning from a raid on London was shot down in Kent, resulting in the Battle of Graveney Marsh, the last action between British and foreign military forces on British mainland soil.[188] On 13 October, Hitler again postponed the invasion "until the spring of 1941"; however, the invasion never happened, and October is regarded as the month regular bombing of Britain ended.[148] It was not until Hitler's Directive 21 was issued, on 18 December 1940, that the threat of invasion finally dissipated.[148] During the battle, and for the rest of the war, an important factor in keeping public morale high was the continued presence in London of King George VI and his wife Queen Elizabeth. When war broke out in 1939, the King and Queen decided to stay in London and not flee to Canada, as had been suggested.[nb 27] George VI and Elizabeth officially stayed inBuckingham Palace throughout the war, although they often spent weekends at Windsor Castle to visit their daughters, Elizabeth (the future queen) and Margaret.[189] Buckingham Palace was damaged by bombs which landed in the grounds on 10 September, and on 13 September, more serious damage was caused by two bombs which destroyed the Royal Chapel. The royal couple were in a small sitting room about 80 yards from where the bombs exploded.[190][191] On 24 September, in recognition of the bravery of civilians, King George VI inaugurated the award of the George Cross. Overall, by 2 November, the RAF fielded 1,796 pilots, an increase of over 40% from July 1940's count of 1,259 pilots.[192] Based on German sources (from a Luftwaffe intelligence officer Otto Bechtle attached to KG 2 in February 1944) translated by the Air Historical Branch, Stephen Bungay asserts German fighter and bomber "strength" declined without recovery, and that from August – December 1940, the German fighter and bomber strength declined by 30 and 25 percent.[4] In contrast, Williamson Murray, asserts (using translations by the Air Historical Branch) that 1,380 German bombers were on strength on 29 June 1940,[193][18] 1,420 bombers on 28 September,[194] 1,423 level bombers on 2 November[195] and 1,393 bombers on 30 November 1940.[195] In July – September the number of Luftwaffe pilots available fell by 136, but the number of operational pilots had shrunk by 171 by September. The training organisation of the Luftwaffe was failing to replace losses. German fighter pilots, in contrast to popular perception, were not afforded training or rest rotations unlike their British counterparts.[196] The first week of September accounted for 25 per cent of the Fighter Command, and 24 per cent of the Luftwaffe's overall losses.[197] Between the dates 26 August – 6 September, the Germans destroyed more aircraft than they lost on only one day (1 September). Losses were 325 German and 248 British.[198] Luftwaffe losses for August numbered 774 aircraft to all causes, representing 18.5 per cent of all combat aircraft at the beginning of the month.[199] Fighter Command's losses in August were 426 fighters destroyed,[200] amounting to 40 per cent of 1,061 fighters available on 3 August.[201] In addition, 99 bombers and 27 other types were destroyed between 1 and 29 August.[202] From July to September, the Luftwaffe's loss records indicate the loss of 1,636 aircraft, 1,184 to enemy action.[193] This represented 47 per cent of the initial strength of single-engined fighters, 66 per cent of twin-engined fighters, and 45 per cent of bombers. This indicates the Germans were running out of aircrews as well as aircraft.[203] Throughout the battle, the Germans greatly underestimated the size of the RAF and the scale of British aircraft production. Across the Channel, the Air Intelligence division of the Air Ministry consistently overestimated the size of the German air enemy and the productive capacity of the German aviation industry. As the battle was fought, both sides exaggerated the losses inflicted on the other by an equally large margin. However, the intelligence picture formed before the battle encouraged the German Air Force to believe that such losses pushed Fighter Command to the very edge of defeat, while the exaggerated picture of German air strength persuaded the RAF that the threat it faced was larger and more dangerous than was the case.[204] This led the British to the conclusion that another fortnight of attacks on airfields might force Fighter Command to withdraw their squadrons from the south of England. The German misconception, on the other hand, encouraged first complacency, then strategic misjudgement. The shift of targets from air bases to industry and communications was taken because it was assumed that Fighter Command was virtually eliminated.[205] Between the 24 August and 4 September German serviceability rates, which were acceptable at Stuka units, were running at 75% with Bf 109s, 70% with bombers and 65% with Bf 110s, indicating a shortage of spare parts. All units were well below established strength. The attrition was beginning to affect the fighters in particular."[206] By 14 September theLuftwaffe's Bf 109 Geschwader possessed only 67 percent of their operational crews against authorised aircraft. For Bf 110 units it was 46 per cent; and for bombers it was 59 per cent. A week later the figures had dropped to 64 per cent, 52 per cent, and 52 per cent.[203] Serviceability rates in Fighter Command's fighter squadrons, between the 24 August and 7 September, were listed as: 64.8% on the 24 August; 64.7% on 31 August and 64.25% on the 7 September 1940, indicating a slow decline.[201] Due to the failure of the Luftwaffe to establish air supremacy, a conference assembled on 14 September at Hitler's headquarters. Hitler concluded that air superiority had not yet been established and "promised to review the situation on 17 September for possible landings on 27 September or 8 October. Three days later, when the evidence was clear that the German Air Force had greatly exaggerated the extent of their successes against the RAF, Hitler postponed Sealion indefinitely."[207] The Battle of Britain marked the first defeat of Hitler's military forces, with air superiority seen as the key to victory.[208] Pre-war theories led to exaggerated fears of strategic bombing, and British public opinion was invigorated by having come through the ordeal.[209] For the British, Fighter Command had achieved a great victory in successfully carrying out Sir Thomas Inskip's 1937 air policy of preventing the Germans from knocking Britain out of the war. The Fighter Command was so successful that the conclusion to Churchill's famous 'Battle of Britain' speech made in the House of Commons on 18 June, has come to refer solely to them: "...if the British Empire and its Commonwealth lasts for a thousand years, men will still say, 'This was their finest hour.'"[210][nb 28] The Battle also signalled a significant shift in US opinion. During the battle, many people from the U.S. accepted the view promoted by Joseph Kennedy, the U.S. ambassador in London, and believed that Great Britain could not survive. However, Roosevelt wanted a second opinion, and sent "Wild Bill" Donovan on a brief visit to Britain; he became convinced Britain would survive and should be supported in every possible way.[211][212] Both sides in the battle made exaggerated claims of numbers of enemy aircraft shot down. In general, claims were two to three times the actual numbers, because of the confusion of fighting in dynamic three-dimensional air battles. Postwar analysis of records has shown that between July and September, the RAF claimed 2,698 kills, while the Luftwaffe fighters claimed 3,198 RAF aircraft downed. Total losses, and start and end dates for recorded losses, vary for both sides. Luftwaffe losses from 10 July to 30 October 1940 total 1,652 aircraft, including 229 twin- and 533 single-engined fighters.[213] In the same period, RAF Fighter Command aircraft losses number 1,087, including 53 twin-engined fighters.[213] To the RAF figure should be added 376 Bomber Command and 148 Coastal Command aircraft conducting bombing, mining, and reconnaissance operations in defence of the country.[4] Dr. Andrew Gordon, who lectures at the Joint Services Command and Staff College, and a former lecturer Professor Gary Sheffield, have suggested the existence of the Royal Navy was enough to prevent the Germans from invading;[214] even had the Luftwaffe won the air battle, the Germans had limited means with which to combat the Royal Navy, which would have intervened to prevent a landing. Some veterans of the battle point out the Royal Navy would have been vulnerable to air attack by the Luftwaffe if Germany had achieved air superiority,[215]citing the fate of Prince of Wales and Repulse which, in December 1941, were sunk in an attack by Japanese aircraft.[215] However, in late May 1941, the Royal Navy was able to completely defeat the attempted seaborne invasion of Crete, despite overwhelming, and completely undisputed, Luftwaffe supremacy.[216] Though the claims about the Royal Navy's ability to repel an invasion may be contested, there is a consensus among historians the Luftwaffe simply could not crush the RAF. Stephen Bungay described Dowding and Park's strategy of choosing when to engage the enemy whilst maintaining a coherent force as vindicated. The RAF proved to be a robust and capable organisation which was to use all the modern resources available to it to the maximum advantage.[217] Richard Evans wrote: A more considered view of the battle has to take into account the vital role of the Royal Navy. It was widely acknowledged by both sides that the only way of achieving a successful invasion of the British Isles was through the establishment of naval supremacy. Given the inability of the Luftwaffe' to effect real damage on the RN throughout the Battle and during the Dunkirk and Norwegian campaigns, as well as the lack of surface assets in the Kreigsmarine's inventory, sea control of the Channel by Germany was impossible. As one of 'the Few', Wg Cdr H R Allen said, "It was sea power that ruled the day in 1940, and fortunately Britain had a sufficiency. The air situation was, of course, important, but by no means fundamental. Without doubt the five hundred of so section, flight and squadron commanders in Fighter Command earned their laurels. But the real victor was the Royal Navy, the Silent Service."[220] The Luftwaffe had 1,380 bombers on 29 June 1940. By 2 November 1940 this had increased to 1,423,[221] and to 1,511 by 21 June 1941, prior to Operation Barbarossa, but showing a drop of 200 from 1,711 reported on 11 May 1940.[222][223][nb 30] 1,107 single- and 357 twin-engined daylight fighters were reported on strength prior to the Battle on 29 June 1940, compared to 1,440 single- and 188 twin-engined fighters, plus 263 night fighters, on 21 June 1941.[222][193] The Germans launched some spectacular attacks against important British industries, but they could not destroy the British industrial potential, and made little systematic effort to do so. Hindsight does not disguise the fact that the threat to Fighter Command was very real, and for the participants it seemed as if there was a narrow margin between victory and defeat. Nevertheless, even if the German attacks on the 11 Group airfields which guarded southeast England and the approaches to London had continued, the RAF could have withdrawn to the Midlands out of German fighter range and continued the battle from there.[224] The victory was as much psychological as physical. Alfred Price: The truth of the matter, borne out by the events of 18 August is more prosaic: neither by attacking the airfields, nor by attacking London, was the Luftwaffe likely to destroy Fighter Command. Given the size of the British fighter force and the general high quality of its equipment, training and morale, the Luftwaffe could have achieved no more than a Pyrrhic victory. During the action on 18 August it had cost the Luftwaffe five trained aircrewmen killed, wounded or taken prisoner, for each British fighter pilot killed or wounded; the ratio was similar on other days in the battle. And this ratio of 5:1 was very close to that between the number of German aircrew involved in the battle and those in Fighter Command. In other words the two sides were suffering almost the same losses in trained aircrew, in proportion to their overall strengths. In the Battle of Britain, for the first time during the Second World War, the German war machine had set itself a major task which it patently failed to achieve, and so demonstrated that it was not invincible. In stiffening the resolve of those determined to resist Hitler the battle was an important turning point in the conflict.[225] The British triumph in the Battle of Britain was won at a heavy cost. Total British civilian losses from July to December 1940 were 23,002 dead and 32,138 wounded, with one of the largest single raids on 19 December 1940, in which almost 3,000 civilians died. The brilliant leadership of Dowding and Keith Park in successfully proving their theories of air defence, however, had created enmity among RAF senior commanders and both were sacked from their posts in the immediate aftermath of the battle.[226] The end of the battle allowed Britain to rebuild its military forces and establish itself as an Allied stronghold. Britain later served as a base from which the Liberation of Western Europewas launched.[29] Winston Churchill summed up the effect of the battle and the contribution of Fighter Command with the words, "Never in the field of human conflict was so much owed by so many to so few".[155][227] Pilots who fought in the Battle have been known as The Few ever since. Battle of Britain Day is commemorated in the United Kingdom on 15 September. Within theCommonwealth, Battle of Britain Day is usually observed on the third Sunday in September. In some areas in the British Channel Islands, it is celebrated on the second Thursday in September. The story of the battle was documented in, amongst many others, the 1969 film Battle of Britain, which drew many respected British actors to act key figures of the battle, including SirLaurence Olivier as Hugh Dowding and Trevor Howard as Keith Park. It also starred Michael Caine, Christopher Plummer and Robert Shaw as Squadron Leaders. Former participants of the battle served as technical advisors including Douglas Bader, James Lacey, Robert Stanford Tuck, Adolf Galland and Dowding himself. An Italian film around the same time titledEagles Over London (1969) also featured the Battle of Britain. It was also the subject of the 1941 Allied propaganda film Churchill's Island, winner of the first-ever Academy Award for Documentary Short Subject.[228] In 2010, actor Julian Glover played a 101-year-old Polish veteran RAF pilot in the short film, Battle for Britain.[229]RAF strategy
[edit]The Dowding System
[edit]Groups
[edit]Control systems
[edit]Sectors
[edit]Limitations
[edit]Effect of signals intelligence
[edit]Air-sea rescue
[edit]Tactics
[edit]Bomber and Coastal Command contributions
[edit]Phases of the battle
[edit]Channel battles
[edit]Main assault
[edit]The Luftwaffe targets RAF airfields
[edit]Battle
[edit]Impact of offensive
[edit]Raids on British cities
[edit]Attrition statistics
[edit]Aftermath
[edit]Battle of Britain Day
[edit]Film
[edit]See also
Saturday, 6 August 2011
Further information: RAF Fighter Command Order of Battle 1940
Further information: List of officially accredited Battle of Britain squadrons
Main articles: The Blitz and Battle of Britain Day
The war against England is to be restricted to destructive attacks against industry and air force targets which have weak defensive forces... The most thorough study of the target concerned, that is vital points of the target, is a pre-requisite for success. It is also stressed that every effort should be made to avoid unnecessary loss of life amongst the civilian population.[177]
Irrespective of whether Hitler was really set on this course, he simply lacked the resources to establish the air superiority that was the sine qua non of a successful crossing of the English Channel. A third of the initial strength of the German air force, the Luftwaffe, had been lost in the western campaign in the spring. The Germans lacked the trained pilots, the effective fighter planes, and the heavy bombers that would have been needed.[218][nb 29]
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