4
. Deighton,
Blitzkrieg
, 244.
5
. Bond,
Chief of Staff
, 316.
6
. Liddell Hart,
The Rommel Papers
, 32.
7
. Barnett,
The Collapse of British Power
, 8.
8
. Deighton,
Blitzkrieg
, 258; Colville,
Man of Valour
, 217.
9
. See Badsey, in Bond and Taylor,
The Battle for France and Flanders 1940.
10
. Trevor-Roper,
Hitler’s War Directives
29; Legro,
Cooperation under Fire
, 94-143.
11
. Lindsay,
Forgotten General
, 140-41.
12
. Milligan,
Adolf Hitler, My Part in His Downfall
, 24-40.
13
. Ponting,
1940: Myth and Reality
, 104-14; Roberts,
The Holy Fox
, 231-36.
14
. Calder,
The Peoples War
, 93.
15
. Glover,
Invasion Scare 1940
, 99.
16
. Schenk,
Invasion of England 1940
, 25.
17
. Deighton,
Fighter
, 262.
18
. Wheeler-Bennett,
King George VI
, 460.
19
. Calder,
The People’s War
, 194.
20
. Cox,
Operation Sea Lion
, 155.
21
. Long,
To Benghazi
, 307.
22
. Glover,
Invasion Scare 1940
, 114.
23
. Barnett,
The Collapse of British Power
, 593.
Charles Messenger
On June 18, 1940, Prime Minister Winston Churchill told the House of Commons: “The Battle of France is over. I expect the Battle of Britain is about to begin.” France was negotiating an armistice with Germany, which would be signed four days later. Continental Europe’s offshore island now stood alone against Hitler. Few outsiders believed that Britain could hold out without making some form of peace with Nazi Germany.
The Germans had already recognized during the Phony War that they might be forced to invade Britain. Grand Admiral Raeder had ordered the OKM to study the problem during the autumn of 1939. Hitler saw the navy’s proposals early in January 1940 and ordered the OKW to coordinate the drawing up of a triservice contingency plan for invading Britain under the code name Sea Lion. The planners recognized that for the landings to succeed, two prerequisites had to be met. First, the Royal Navy had to be prevented from interfering with the passage of the invasion forces across the English Channel. Second, the Luftwaffe had to achieve air supremacy over southern England. Raeder knew that his surface fleet was not strong enough to risk open battle with the British Home Fleet. He concluded that the best way in which the Channel could be made a “no go” area to the Royal Navy was to use the Luftwaffe to dominate it. This, as Göring accepted, was certainly feasible once France and the Low Countries had been overrun.
By the end of January 1940, Hitler had approved of the OKW plan for the invasion of Britain in principle. This largely influenced his decision to amend Case Yellow in accordance with the proposals put forward by Generals Gerd von Rundstedt and Erich von Manstein. Afterward, the attention of the German high command was absorbed by Norway and putting Case Yellow into effect. Once France had fallen, Hitler’s hopes that Britain might immediately seek terms were dampened by Churchill’s pugnacious speech of June 18. The OKW had also informed him that it would take six weeks to prepare the cross-Channel invasion force, which included gathering sufficient shipping. Hitler did not want to give the British the chance to recover their strength after their defeat in France, and was not prepared to wait until the end of July before mounting his attack. He therefore decided on a change of plan. The Luftwaffe’s attacks against Warsaw in September 1939 and, more recently, Rotterdam, had accelerated the Polish and Dutch surrenders. Likewise, the French declaration that Paris was an open city and the triumphant entry of his troops into the French capital had been the final nail in France’s coffin. Hitler was sure that if London was threatened in the same way, the British people would seek peace, rendering an opposed invasion, with all its risks, unnecessary. But first he had to make the British feel vulnerable. He needed to destroy what air defenses they had and also ensure that their traditional shield, the Royal Navy, was perceived by the British to be powerless. He discussed his thoughts with Hermann Göring. The Reichsmarschall was enthusiastic. For the first time in history, air power would achieve victory on its own, without the active participation of the two more traditional services.
The Germans were well aware that the so-called “Miracle of Dunkirk” had enabled a significant proportion of the British Expeditionary Force (BEF) to be rescued, though they also knew it had been forced to leave most of its heavy weaponry behind in France. The Royal Navy had lost a number of destroyers off the beaches to air attack. The capital ships of the Home Fleet remained at their wartime base at Scapa Flow in the Orkneys. It would take them twenty-four hours’ steaming time to reach the Channel. The RAF had also suffered heavily during the battle for France. Apart from the casualties inflicted on the BEF’s Air Component and the Advanced Air Striking Force, Air Chief Marshal Sir Hugh Dowding, the AOCinC of the Fighter Command, had been unable to resist Churchill’s demands to help shore up the French by sending additional fighter squadrons to France. On May 15 Dowding had complained to the War Cabinet about the dissipation of his precious fighter strength, but his pleas fell largely on deaf ears. All Churchill would countenance was that only Hurricanes would be earmarked, thus at least enabling Dowding to preserve his Spitfires, which made up one-third of his strength, for the defense of Britain. The ten squadrons, which had been demanded by French Prime Minister Paul Reynaud, were therefore sent. The subsequent air battles over France and those over the Dunkirk beaches, which also drew in Dowding’s fighters based in Britain, resulted in the loss of nearly 500 fighters and some 290 pilots.
Göring knew that the RAF had suffered, but the Luftwaffe, too, had taken losses during the recent campaign. Indeed, Luftflotten 2 and 3 had lost over a quarter of their initial aircraft strength. Some 3,000 air crew had been killed and a further 1,500 wounded. The surviving crews were tired after six weeks’ continuous fighting, and many of the French airfields the Germans had taken over needed repair. Furthermore, the Luftwaffe’s signals network needed to be switched through 180 degrees to control operations against Britain effectively. To allow time for reorganization and recuperation, Göring issued a warning order on June 20, ordering Luftflotten 2 and 3, as well as Luftflotte 5 in Scandinavia, to be ready to mount full-scale attacks on England on July 1. In the meantime, numerous photographic reconnaissance sorties were to be flown to bring intelligence on RAF airfields up to date. Many of these missions were carried out by the Junkers 86P. With its twin turbo-supercharged Jumo 207 and pressurized cabin enabling it to fly at altitudes at well over 40,000 feet, no RAF fighter could intercept it. However, the photographs it could take at these heights lacked the definition needed to identify particular types of aircraft on the ground. Consequently, lower level reconnaissance had to be carried out, using types like the Dornier 215B. While this did produce photographs to identify the fighter airfields, a significant number of these aircraft were intercepted and shot down. It confirmed to Göring’s planners that the chain of radar stations on the English east and south coasts was crucial in the British defenses. They were certain that without radar, the RAF could not possibly have scrambled its fighters in time.
The Luftwaffe’s final plan was completed on June 29. As had been the tactic during the blitzkrieg campaigns, the objective was to destroy as much as possible of the RAF’s fighter strength on the ground. Simultaneously, the Home Chain radar system had to be destroyed. The latter task was given to the Stuka wings and the specialist precision-attack Me 110 fighter-bomber Erprobungsgruppe 210, which was commanded by Condor Legion veteran Hauptmann Walther Rubensdörffer. The Me 110 group had Bf 109s as part of its establishment, but additional Bf 109s would be provided to escort the Stukas. Simultaneous with the assault on the radar stations, the bomber wings of Luftflotten 2 and 3 would attack fighter airfields lying south of the River Thames. A few detachments would attack shipping targets of opportunity in the English Channel in order to draw RAF fighters away from their airfields. Hans-Jürgen Stumpff’s Luftflotte 5 would not take part in the initial assault, but would strike later to throw the British air defenses off balance. Once the Luftwaffe had achieved air supremacy, Hitler would issue an ultimatum to Churchill—make peace or London will be subjected to a devastating air attack. If there was no positive response, the attack would be carried out.
By the end of June the two German air fleets, on which the main burden of subduing Britain rested, were almost ready for operations. Some of the recently occupied airfields in France still needed work done on them, but with a certain amount of improvization, they were functional. Aircraft serviceability was more of a problem. The strains of the recent campaign meant that routine servicing had suffered, and it was imperative that the maximum possible strength of operational aircraft be achieved for the launch of the campaign against Britain. The July 1 deadline proved to be too ambitious, and Göring, having referred the matter to the Führer, agreed to a forty-eight-hour postponement.
The combined operational strength of Luftflotten 2 and 3 for what Göring codenamed Adlerangriff (“Eagle Assault”) consisted of some 650 Bf 109s, 250 Me 110s, 275 Ju 87s, and 920 bombers. Luftflotte 5 was smaller and had thirty-nine Bf 109s, which did not have the range to reach Britain, twenty Me 110s, and 100 bombers. Luftwaffe intelligence estimated the RAF’s strength as some 650 fighters and 750 bombers, but believed that the greater combat experience of its crews would tip the balance. Furthermore, they considered the RAF’s command and control structure to be too rigid. Their conclusion was that the initial strike would so cripple Britain’s air defenses that air supremacy would be quickly gained.
In fact, the Luftwaffe overestimated the RAF’s fighter strength. The ravages of the recent air battles over the continent meant that, at the beginning of July, Dowding could only muster nineteen Hurricane and the same number of Spitfire squadrons, with an operational total of 240 Hurricanes and 235 Spitfires, well below the Luftwaffe’s estimate. It was true that fighter production was on the increase—over 300 Hurricanes and nearly 100 Spitfires rolled off the assembly lines during June 1940 alone—but Dowding was suffering from a serious shortage of trained fighter pilots. Only thirty-nine were being produced by the training system every two weeks. He had just set up three additional operational training units, which would enable the output to be trebled, but it would be a few weeks before the operational squadrons could enjoy the benefits. In the meantime, they would have to get on as best as they could.
Dowding recognized only too well that the Germans needed to establish at least overwhelming air superiority over southern England to ensure that an invasion was successful. Southeast England was clearly the region under greatest threat, since it was closest to the continent. Keith Park’s number 11 Group was responsible for its defense, and Dowding allocated it the largest number of squadrons—seven Hurricane and seven Spitfire. But he also had to guard against invasion farther west, and so gave Quintin Brand and his number 10 Group, which covered the remainder of southern England, six Hurricane and five Spitfire squadrons. Trafford Leigh-Mallory’s 12 Group north of the River Thames provided immediate backup to the two forward groups, with five Hurricane and five Spitfire squadrons. Finally, there was Air Vice Marshal Richard Saul’s 13 Group, which covered the north of England and southern Scotland. Dowding considered the threat to this region significantly less than that faced by the other three groups so he merely gave Saul the slender balance of operational squadrons—one Hurricane and two Spitfire, together with two squadrons of inferior Defiants.
Dowding’s plan was that new fighter squadrons should form in number 13 Group’s area and, once operational, replace tired and depleted squadrons from the forward groups. Each group was divided into a number of sectors and had its own operations room from which it controlled the squadrons allotted to it.