Operation Sea Lion

John Florens | Apr 25, 2024

Table of Content


Operation Sea Lion (German: Unternehmen Seelöwe) was a German operational plan for the invasion of the United Kingdom during the Second World War, after the defeat of France. To ensure the success of the operation it was necessary to secure air and naval superiority in the English Channel region. This objective was not achieved by the Germans during or after the Battle of Britain. On 17 September 1940, Operation Sea Lion was indefinitely postponed and no further attempts were made to execute it.

Adolf Hitler decided as early as November 1939 to "settle" all the problems in the West by invading Belgium, the Netherlands and France. Considering the possibility of the Channel ports coming under the control of the Kriegsmarine, Großadmiral Erich Raeder tried to anticipate the steps to be taken after victory on the continent. The Grand Admiral asked his operations officer, Kapitän Hans Jürgen Reinicke, to make an analysis of a possible landing in England. Reinicke completed his preliminary report in five days and identified a number of binding premises:

In December 1939, the German Land Forces Command designed its own study and solicited the views of the Kriegsmarine and Luftwaffe. The Land Forces' plan envisaged an attack on the east coast of England between The Wash and the Thames by troops from the Low Countries ports that had crossed the North Sea. Reichsmarschall Hermann Göring, the Luftwaffe commander, responded with a one-page letter declaring that a combined action aimed at landing in England should not be the initial act of war, but the one that would end a victorious war. The Kriegsmarine's reply was even more concise, outlining all the difficulties to be overcome in the event of an invasion of England.

Sometime later, in the spring of 1940, the Kriegsmarine became even more reserved about invading the UK because of the 'victory' in the Norwegian campaign (Weserübung). After Weserübung, the Kriegsmarine had only one heavy cruiser, two light cruisers and four operational destroyers. Admiral Raeder was an avowed opponent of Operation Sea Lion, he taking into account that almost all German surface fleet vessels had been sunk or badly damaged, with the Kriegsmarine's strength overwhelmingly outnumbered by Royal Navy vessels.

On 16 July 1940, after the victorious campaign in the Netherlands and France, Hitler, whose peace proposals had been rejected by the British, issued Directive (Weisung) No 16, setting out the steps for organising the landing in England. The Führer prefaced his order with the fact that England, despite a military situation the Führer described as "hopeless", showed no sign of being willing to accept peace negotiations. The objective of the operation, as Hitler saw it, was to eliminate the bases of attack against Germany, and the fighting could continue until England was fully occupied.

Hitler's directive set four conditions for launching the invasion:

This last provision placed the responsibility for the success of the operation mainly on the shoulders of Raeder and Göring. Neither of them were supporters of the landing, indeed, they were almost openly disapproving of it. Directive 16 did not provide for the establishment of a combined operational headquarters to coordinate the three branches of the military (ground forces, navy and air force) during the planning and for the coordination and execution of such a complex action (unlike the Allies, who created the Supreme Headquarters Allied Expeditionary Force (SHAEF) for the Normandy landings).

When he learned of Hitler's intentions through his foreign minister, Galeazzo Ciano, Italian dictator Benito Mussolini offered to participate in the invasion with ten infantry divisions and thirty air squadrons. Hitler at first refused the offer, but eventually accepted the participation of a small contingent of Corpo Aereo Italiano fighter and bomber planes to take part in the Luftwaffe's air campaign in October

Heeresgruppe A

Commandant Generalfeldmarschall Gerd von Rundstedt

Heeresgruppe C

Generalfeldmarschall Wilhelm Ritter von Leeb

Battle of Britain

Beginning in August 1940, the Luftwaffe began a series of concentrated attacks - Unternehmen Adlerangriff - on targets in the United Kingdom to destroy the RAF and gain air superiority over Britain. The campaign later became known as the Battle of Britain. Changing the focus of the bombing from attacking RAF bases and radar stations to attacking London turned Adler into a strategic bombing. The effects of this change are the subject of controversy. A number of historians believe that the change in strategy caused the Lufewaffe to lose the battle for air superiority. Other historians believe that the Luftwaffe achieved insignificant results even in the early part of the campaign, and that the RAF had not reached the brink of collapse, as is sometimes claimed. Another view is that the Germans would not have been able to achieve air superiority before weather conditions worsened in the autumn. There is also the view that the Luftwaffe was unlikely to be able to destroy RAF Fighter Command. If British losses had become very heavy, the RAF would have simply withdrawn its aircraft to the north and regrouped. After that, they would redeploy their forces south as soon as the Germans launched the invasion. There is also the view that the Sea Lion would have failed anyway, due to the weakness of the German navy.

The view that the "Sea Lion" would have been a failure regardless of a possible German victory in the air battle was shared by a number of staff officers. Grand Admiral Karl Dönitz considered air superiority insufficient. Dönitz declared that the Germans had neither control of the airspace nor the seas, nor did they have any chance of conquering them. Erich Raeder, commander of the Kriegsmarine in 1940, believed that the British had never mobilised their entire fleet for combat. He further believed that a German invasion of England would be a matter of life and death for the British, who would not hesitate to commit the entire naval force to every last ship and man in the fight for survival. The Admiral noted that the Luftwaffe was capable of defending German shipping against raids by the British fleet and felt that the German air force was not capable of making up for the inferiority of the Kriegsmarine in the short term either.

When Franz Halder, Chief of the Land Forces General Staff, found out what the state of the Kriegsmarine was and what the views were on the invasion plan, he noted in his diary on 28 July 1940 that if all that was heard about the navy's plan was true, the whole invasion plan could be safely dropped.

Alfred Jodl, head of operations of the OKW (Oberkommando der Wehrmacht), remarked after Raeder admitted that the Kriegsmarine could not meet the operational requirements of the ground forces that a landing in England was to be regarded only as a desperate act.

Luftwaffe limits

The Luftwaffe's record in surface combat up to that point was poor. During the Norwegian campaign, despite eight weeks of air superiority, the Luftwaffe managed to sink only two British warships. German crews were untrained and aircraft were not equipped to attack moving naval targets, especially destroyers and fast torpedo boats. The Luftwaffe was also not equipped with naval armour penetrating bombs, nor were they equipped with torpedoes, essential in the fight against large ships. The Luftwaffe carried out 21 attacks against small torpedo boats during the Battle of Britain without managing to sink even one. The British had between 700 and 800 torpedo boats and fast starships, which could become a major threat to the Germans if the Luftwaffe was unable to destroy them. Only nine torpedo boats out of a total of one hundred and fifteen sunken ships were destroyed by German aircraft throughout the war. Only nine British destroyers out of over one hundred operational were sunk by air raids in 1940. Of these, five were sunk during the evacuation of British troops from Dunkirk, despite a long period of German air superiority, hundreds of tons of bombs dropped and numerous missions in the region. The Luftwaffe's record in sinking merchant ships was also modest. The German air force sank about 1% of the ships that sailed in British waters in 1940. Most British merchant ships sank after colliding with sea mines.

In case of an invasion, the Germans had equipped the Me 110s of Erprobungsgruppe 210 with so-called "Seilbomben". The latter were secret weapons that were to be used to cause a blackout across the south-east of England. The equipment to launch the wires that would have shorted the power lines was mounted on Me 110 aircraft. Essentially, it involved dropping wires over power lines, a dangerous operation for crews and aircraft.

The Germans' biggest problem in protecting an invasion fleet was the small size of their navy. The Kriegsmarine, which was numerically inferior to the Royal Navy anyway, had already lost several of its modern surface ships in April 1940 during the invasion of Norway. The loss of two light cruisers and ten destroyers was particularly significant, as such ships were best suited for the Channel battles where the invasion was to take place. Submarines (U-boats), the Kriegsmarine's most powerful weapon, were intended to destroy enemy ships, not support the invasion.

Although the Royal Navy could not use all of its available ships in the English Channel, as a large part of the fleet was engaged in battles in the Atlantic and Mediterranean, the Home Fleet still had a great numerical advantage over the Germans. It is debatable whether British surface ships were as vulnerable to air attack as the Germans had hoped. During the Dunkirk evacuation, relatively few British ships were sunk, despite being stationary targets. The total differences between the surface fleets of the two forces made an amphibious invasion very risky, regardless of the results of air attacks. In addition, the Kriegsmarine used the rest of its large surface ships in diversionary operations in the North Sea.

The Frisian fleet, one of the most powerful and modern in the world at the time, could have tipped the scales against the British if captured by the Germans. The pre-emptive British attack at Mers-el-Kébir and the scuttling of the French fleet at Toulon prevented the rise of German naval power.

Even if the Royal Navy had been neutralised, the chances of a successful amphibious invasion would have been slim. The Germans had no specialised landing craft and would have had to use mainly river barges to transport troops and supplies. Barges would have limited the volume of artillery pieces and the number of tanks that could be transported to the island and would have limited operations to periods of high calm. River barges were not designed to be used at sea and even in perfect weather conditions would have moved slowly, vulnerable to all types of attack. In addition, there were not even a sufficient number of barges to transport the first wave of invasion, let alone the next waves and their equipment. The Germans needed to capture a port immediately, an unlikely prospect given the high defensive capability of British coastal defences in the south-east. The British had also prepared themselves, putting in place a series of defence plans in case of invasion, including measures such as the use of combat gas.

Landing craft

In 1940, the German navy was ill-prepared to mount an amphibious attack on the scale of Operation Sea Lion. The navy lacked both specially built landing craft and the experience and doctrine of amphibious warfare. For the Sea Lion, the German navy was practically starting from scratch. A number of efforts had been made in the interwar period to experiment with landings, but without any notable results.

The Navy made limited progress in the development of landing craft with the construction of the Pionierlandungsboot 39 (Engineer Landing Ship 39), a self-propelled, shallow-draft vessel that could carry 45 infantrymen, two light vehicles and 20 tons of supplies. By the end of September 1940 only two prototypes had been delivered

The Navy began developing a vessel capable of transporting and landing both large infantry units and tanks - the 200-tonne 'Marinefährprahm'. However, these large landing craft were not ready for Operation Sea Lion in 1940, the first being launched only in April 1941.

With only two months to organise an invasion fleet, the Kriegsmarine chose to convert river barges into landing craft. 2,400 barges were requisitioned from all over Europe, (860 from Germany, 1,200 from the Netherlands and Belgium and 350 from France). Of these, only 800 were self-propelled, with the remainder to be towed.

Two main types of barges were available for Operation Sea Lion. The first was the 360t, 38.5m long Peniche and the second was the 620t, 50m long Kampine. The Germans requisitioned 1,336 barges classified as péniches and 982 considered Kampinen. For the sake of simplicity, the Germans considered any barge up to 360 t to be 'type A1' and those larger than that to be 'type A2'.

Armoured vehicles

Providing support to the first waves of landings by armoured vehicles was a critical issue for the operation planners. They worked hard to find a practical solution for landing tactics on the invasion beaches. Although Type A barges could land medium-sized tanks on the open beaches, this could only be done during low tide when the transport ships were on solid ground. The time required to assemble the outer ramps meant that both armour and engineer crews were under enemy fire for some time. For this reason, the Germans sought to find a quicker and safer method of getting the armour onto the beach. Tanks that floated and others that were completely submersible were created.

The Schwimmpanzer II was a modified version of the Panzer II which, despite its weight of 8.9 t, could be made to float by attaching parallelepiped floats. The floats were made of aluminium and were filled with non-metallic fibreglass. Propulsion was provided by caterpillars which, by means of rods, were attached to the shaft of a propeller. The Schwimmpanzer II could travel 5.7 km

The Tauchpanzer, also known as U-Panzer or Unterwasser Panzer (underwater tank) was a modified Panzer III or Panzer IV medium tank with a sealed turret. The space between the turret and the armour was sealed with an inflatable hose, and the gun and machine gun mantles and muzzles as well as the commander's cupola were covered with plugs of a special rubber. Once the tank was ashore, all covers and seals were removed by detonating explosive charges.

The air needed to run the engine and keep the crew alive was sucked into the tank through an 18 m long hose, held at the surface of the water by a float. An antenna was also attached to the float, allowing radio communication between the tank crew and the transport barge. The tank's engine had been modified to allow seawater cooling and the exhaust pipes were fitted with discharge valves. Water seeping into the tank could be removed with internal pumps. Underwater navigation was by directional gyro and radio instructions from operators on the transport barges.

Tests carried out in late June and July at Schilling, near Wilhelmshaven, showed that the submersible tanker worked well when moving along the seabed. When stopped for any reason, the tanks tended to sink in the sand. Underwater obstructions - ditches or large rocks - could stop the tanks moving forward. For this reason it was decided to launch the tanks into the water during the tide, which would allow the bogged tanks to be recovered during the ebb tide. The submersible tanks had been designed to operate to a depth of 15 m.

Kriegsmarine had made plans to use 50 specially modified cable-laying vessels, but tests showed that this type of vessel was not suitable. The ballast needed to counterbalance the tanks and the fact that the vessel had to be anchored to prevent capsizing during the placement of armour with cranes on the side launch ramps were major problems that could not be solved. These difficulties led to the design of a new type of barge.

By the end of August, the Germans had converted 160 Panzer IIIs, 42 Panzer IVs and 52 Panzer IIs into amphibious tanks. Thus, at least on paper, the Germans had 254 armoured tanks, roughly an armoured division. The tanks were divided into four battalions called Panzer-Abteilung A, B, C and D. During the invasion, they were to be supplied with enough fuel and ammunition for a range of 200 km.

Special landing equipment

Following a competition launched by the Navy, "heavy landing bridges" were designed, prefabricated docks, much like the Mulberry "ports" used by the Allies in World War II during the Normandy landings. These docks were designed and manufactured by Krupp Stahlbau and Dortmunder Union. Prototypes built spent the winter of 1940-1941 in the North Sea. The Krupp model was chosen because it took only one day to assemble, unlike the Dortmunder Union model, which took twenty-eight days. The Krupp dock consisted of a series of interconnected platforms, each 32 m long and supported on the seabed by four metal legs. The platforms could be raised or lowered with large winches, allowing them to adjust their height according to ebb and flow. The German Navy ordered eight complete Krupp systems, each consisting of six platforms each. The order was reduced to six units in the autumn of 1941, eventually to be cancelled after it became clear that the landing operation would not take place.

In mid-1942, the two prototypes (Krupp and Dormunder) were transported to the Channel Islands, and were installed at Alderney, where they were used to land the materials needed to fortify the islands. The "German Pontoons" (as the locals called them) remained in position until 1978-79, when they were finally dismantled.

The ground forces developed their own portable landing bridge nicknamed Seeschlange (Sea Serpent). This 'floating road' consisted of a series of interconnected modules that could be towed to the landing site, where they were to be used as temporary docks. Vessels anchored at Seeschlange could unload their cargo by crane directly onto the 'road' platform, or into trucks parked alongside. Seeschlange was successfully tested by a special land force unit at Le Havre in the autumn of 1941. These docks were chosen for Operation Herkules, the plan for a German-Italian invasion of Malta...

The Germans designed a specialised vehicle for landing in England - the Landwasserschlepper - an unarmed amphibious tractor, which had been in the works since 1935. The original design was intended as a support vehicle for pontoon troops. Three such tractors were assigned to the 100th armoured detachment as part of the invasion force. The tractors were to pull barges without their own propulsion system onto the beach and tow the vehicles across the sandy beaches. The tractors were also to carry supplies during the six-hour period of low tide, when the barges were no longer floating. The transport was to be done with an amphibious trailer with a capacity of 10-20 t, towed by Landwasserschlepper. General Halder watched a demonstration of the use of the Landwasserschlepper and its tug on 2 August 1940 on the island of Sylt. The General, while objecting to the high height of the vehicle when travelling overland, recognised the usefulness of the prototype. There were proposals to equip each invasion barge with one or two amphibious tractors, but production was eventually abandoned.

The German High Command (OKH) initially planned a full-scale invasion, landing 40 divisions in the region from Dorset to Kent. Such a large-scale landing far exceeded the carrying capacity of the Kriegsmarine, which led to the original plans being scaled back. The new plan called for the landing of only nine divisions, which would bring 67,000 infantry to the English coast, and an airborne support division. The landing area was chosen to be between Rottingdean and Hythe.

The German Navy wanted to designate a front as narrow as possible, which would have been easier to defend, according to the sailors. Admiral Raeder wanted the front to stretch from Dover to Eastbourne, recalling that naval transport between Cherbourg

The battle plan called for German forces to be transported from Cherbourg to Lyme Regis, from Le Havre to Ventnor and Brighton, from Boulogne to Eastbourne, from Calais to Folkestone and from Dunkirk and Ostend to Ramsgate. The parachutists were to land near Brighton and Dover. After taking a firm hold of the coast, they would advance north to seize Gloucester and encircle the capital, London. Modern scholars believe that the Germans would not have attempted to storm the capital, but rather besieged and bombarded it. The Germans were to conquer a region of England as far as the 52nd parallel (roughly as far as Northampton), Nazi planners believed that the UK would have surrendered in this situation.

After the German occupation of the Pas-de-Calais region of northern France, it seemed obvious to both the German High Command and Hitler that coastal heavy artillery could impede Allied military and commercial shipping through the Straits of Dover (Pas de Calais). Even Kriegsmarine planners considered that banning Allied traffic through the straits was not only desirable but feasible, especially given the short distance of only 34 km between France and England. For all these reasons, orders were given to station all the heavy artillery pieces of the Army and Navy along the French coast, especially at Pas-de-Calais. This operation was to be carried out by the Todt Organisation and actually began on 22 July 1940.

By early August, four rotating turrets equipped with 28cm guns were ready for battle, as were all the towers mounted on railway platforms. Seven of the 28cm artillery pieces and one 21cm gun with a range of 115km could only be used against ground targets. The remaining thirteen 28cm and five 25cm guns plus the motorised batteries (twelve 24cm and ten 21cm) could be used against naval targets, but were of limited effectiveness due to slow traverse speed, long reloading times and inadequate ammunition.

Much better suited to destroying naval targets proved to be the four naval batteries installed in mid-September: Friedrich August with three 30.5 cm guns, Prinz Heinrich with two 28 cm guns;Oldenburg' with two 24 cm guns and the largest of all, Siegfried, with two 38 cm guns. Fire control for these coastal batteries was provided by reconnaissance aircraft and the DeTeGerät radar system installed at Cap Blanc-Nez and Cap d'Alprech. These radars could detect naval targets up to 40 km away, even small patrol vessels in British territorial waters. Two more radars were deployed in mid-September: a DeTeGerät at Cap de la Hague and a long-range FernDeTeGerät at Cap-d'Antifer near Le Havre.

The ground forces developed plans to place mobile artillery batteries along the British coastline immediately after the beaches were taken, to be used to neutralise British ships. For this purpose Artillery Kommand 106 of the 16th Army was assigned to land with the second wave to ensure protection of the transport fleet as soon as possible. The unit consisted of twenty-five 15cm and seventy-two 10cm guns. At least a third of these were to be landed in England by the end of the first week of the invasion.

These batteries were intended to minimise the threat of British destroyers to shipping vessels on the easternmost route. The batteries were to cover the main shipping routes from Dover to Calais and from Hastings to Boulogne. They could not protect the westernmost routes, but large areas of the invasion zones were still to be under their cover.

British commanders were aware of the threat posed by German artillery dominating Dover Strait and on 4 September 1940 the Chief of the Naval General Staff signed a memorandum in which he emphasised that if the Germans '... could gain control of Dover Strait and capture our defensive guns, then, by controlling these points on both sides of the strait, they might be in a position to largely deny our naval forces access to those waters'. Had the Germans taken the Dover Strait, the Royal Navy would not have been able to interrupt the flow of German supplies and reserve troops across the Channel, at least during daylight hours. He further warned that in this situation the Germans would have been able to provide particular vigour to the attack against British forces. The very next day, the Grand Joint Chiefs of Staff, after considering the importance of the Straits from all points of view, decided to reinforce the defence of the coastal region in the area with new ground troops.

German coastal batteries began firing on naval targets in the second week of August 1940 and continued firing until September 1944. The Germans caused 3,059 alarms, killed 216 civilians and damaged 10,056 targets in the Dover area and, most importantly, inflicted very heavy losses on shipping, probably the heaviest losses suffered by the British outside those suffered during the Battle of Britain.

Both the British and Americans were convinced during the summer of 1940 that the German invasion was imminent. The Germans, for their part, were confident enough to release propaganda films. One crew filmed the landing of tanks and infantry from the Bay of Baje in the Belgian port of Antwerp for two days in early September 1940. As Hitler had been informed that the landing would begin at night, the dictator wanted to show the public all the details of the action.

The British and Americans predicted that the landings would most likely take place during the August 5-9, September 2-7, October 1-6 or October 30-November 4 tides.

On 17 September 1940, Hitler met with Hermann Göring and Gerd von Rundstedt, who managed to convince the Führer that the operation was hopeless. The Germans did not have control of the airspace, and coordination between the various branches of the armed forces left something to be desired. On the afternoon of the same day, Hitler gave the necessary orders to postpone the invasion. He also ordered the invasion fleet dispersed to avoid the destruction of the ships by the British air force and navy.

The postponement of the invasion coincided with rumours of a German landing attempt around 7 September, which was repulsed with heavy losses for the attackers. Stories circulated of large areas of coastal waters being set ablaze by the dumping and igniting of large quantities of oil. Both rumours were presented as credible news in the American press, but both were officially denied by the British and German governments. Historian James Hayward surmised that the "failed invasion" rumours were British propaganda aimed at boosting morale at home and in Nazi-occupied Europe, but convincing Americans that the Yugoslavs were determined to fight to the end.

After the series of strategic bombing raids on British cities from September 1940 to May 1941, Hitler began to pay increasing attention to attacking the Soviet Union, and the Seelöwe fell into disuse, with no further attempts to revive it. However, the last military units destined for the invasion of the United Kingdom would only be reassigned to other missions in February 1942, during preparations for [[Operation Barbarossa

Most military historians believe that Operation Sea Lion would have had no chance of a successful conclusion. Kenneth Macksey believes that the Germans would only have been victorious if the Royal Navy had refrained from large-scale intervention and the invasion had been launched by May 1940, but Macksey concludes that the Germans were not ready for the assault at that time. Other authors (Peter Fleming, Derek Robinson and Stephen Bungay) believe that the operation would have ended in disaster for the Germans, and other scholars have called the German amphibious plan a "Dunkirk in reverse". Robinson believes that the Royal Navy's huge superiority to the Kriegsmarine would have turned "Sea Lion" into a disaster.

Adolf Galland, the Luftwaffe commander during the invasion preparations, said that the plans for the invasion were not serious, and there was a huge sense of relief among the Wehrmacht when the Sea Lion was cancelled. Field Marshal Gerd von Rundstedt shared Galland's view that Hitler had never taken the invasion of England seriously, the whole action being a bluff to try to get the British government to start negotiations. He noted that Napoleon had failed to invade England, and the difficulties the Emperor had to overcome had not been solved by the Sea Lion planners. In fact, in November 1939, German war fleet commanders produced a study on the possibility of invading England in which they concluded that such an action needed to meet two conditions - ensuring air and naval superiority, which Germany would never achieve. Admiral Karl Dönitz believed that air superiority would not be enough and admitted that "We had neither control of the airspace or the seas, nor were we capable of obtaining it" . On 14 August 1940, Hitler told close friends that he would not be prepared to attempt an invasion of the UK if the operation proved dangerous, and added that there were other ways of defeating the British than invasion.


Four years later, D-Day would give the true extent of the stockpiles of materials that needed to be continuously landed to sustain an amphibious invasion. For the Germans, the problem would have been much worse, since German ground forces were not motorised, relying mainly on horse-drawn traction. One of the biggest problems for the Germans would have been transporting and landing thousands of horses. British intelligence calculated that the first landing wave of 11 divisions (including airborne divisions), required an average of 3,300 tons of supplies per day. In Russia, a single German division in 1941 during the heaviest fighting required up to 1,100 tons of supplies per day, and 212-425 tons per day on "normal" days. British strategists calculated that Folkestone harbour, the largest port the Germans would have taken during the initial phase of the invasion, would allow the transit of about 150t of supplies per day in the first week of the invasion (if the harbour equipment had been destroyed and the port's transport capacity reduced by 50% by RAF bombing). Over the course of a week, the port's maximum throughput could be increased to 600 tonnes per day, but only after the Germans had repaired the port facilities and cleared the roadstead of sunken ships and other shanties. This would have meant that for the nine infantry and two paratroop divisions initially landed, no more than 20% of the daily supply requirements would be unloaded in the harbour, with the remainder to be unloaded directly onto the beach, or parachuted in.

Conquering the port of Dover would have increased the unloading capacity by a further 800 tonnes a day, bringing the requirement for supplies handled by protosses to 40%, but this increase was based on the assumption that the Royal Navy or RAF would not be able to seriously disrupt German shipping across the Channel.


From 19 to 26 September 1940, weather conditions in the Channel region where the invasion was to take place were generally good. Crossing the Channel, even with modified river barges, as the sea remained slightly rough. The wind blew moderately for the rest of the month and would not have prevented the first landing wave from achieving its objectives within the ten days originally planned If on 27 September the sea became rougher, with the wind blowing from the north, the crossing could be more risky, calm returned to the sea on 11-12 October and then on 16-20 October. After this, the wind began to blow more strongly from the east, which would have created more favourable conditions for the invasion fleet to cross the English Channel. At the end of October, (according to British Meteorological Service documents), the wind began to blow strongly from the south-west. The force 8 wind would have prevented any landing attempts by modified river barges

German intelligence services

The German intelligence services have had several failures, not least because of MI5's success in persuading spies to work as double agents and provide the Germans with false information. While some of the misinformation would not have caused too many problems others, such as information about bridges that no longer existed, or exaggerating the usefulness of British secondary roads, would have caused major disruption to the deployment of German forces.

Post-war war games

During the 1974 Royal Military Academy Sandhurst war game in which it was assumed that the Luftwaffe had not yet gained air supremacy and continued to make a good effort to bomb London, the German camp managed to establish a bridge capture in south-east England. However, the German advance was halted on the defensive lines (General Headquarters Line) that had been built to repel the expected invasion. These defensive lines were defended by Home Guard volunteers. During the war game it was assumed that, while the Germans were being held back in fighting along the British defensive lines, the regular forces were in the process of mobilising. Just days after the invasion began, Royal Navy ships from the base at Scapa Flow arrived in the English Channel area, blocking the resupply of German troops and the transport of reserve troops. Under these conditions, the already landed German troops, no longer supported by fresh troops from the Continent and supplied only by air, and forced to face the onslaught of British infantry, artillery and armour, were forced to surrender.


Plans for the German administration in occupied Britain called for the country to be divided into six military-economic commands with capitals in London, Birmingham, Newcastle, Liverpool, Glasgow and Dublin... Hitler decided that Blenheim Palace, Winston Churchill's family home, was to be used as the headquarters of the German military occupation government. David Lampe argues in his book The Last Ditch that the Germans only wanted to occupy southern England and that plans had been drawn up to regulate the movement of civilians to and from areas under their control. Some Nazi officials believed that in order to secure German hegemony in Western Europe, the proclamation of independence for several regions should be considered. This would have involved the formation of a Scottish state, a United Ireland and the granting of autonomy to Wales.

OKW, RSHA, and the Foreign Ministry compiled a list of names of trusted individuals who would form a new government, just as in occupied Norway. This list was opened by Oswald Mosley. The RSHA also considered Harold Nicolson useful for taking over leadership positions. The OKW also made plans for suppressing any form of civilian resistance.

After the war, rumours emerged about possible candidates for the post of 'viceroy' - Reichskommissar für Großbritannien (Reichskommissar for Great Britain), who in other occupied territories (Norway or the Netherlands for example) enjoyed dictatorial powers (Josef Terboven or Arthur Seyss-Inquart). At the top of the list would have been the Nazi foreign minister Joachim von Ribbentrop, who had been ambassador to the United Kingdom. The second name mentioned was Ernst Wilhelm Bohle, an undersecretary of the Foreign Ministry and Gauleiter of the NSDAP.

British Monarchy

In a Channel 5 documentary on 16 July 2009 it was claimed that the Germans wanted to restore the reign of Edward VIII if they occupied England. Many Nazi leaders believed that the Duke of Windsor was a Nazi government sympathiser, a belief supported by his and his mistress Wallis Simpson's behaviour during their 1937 visit from Germany. However, the documentary showed that, despite German plans, the former king agreed to be transferred aboard a British warship to the Bahamas, where he took over as governor. In this way, he could in no way serve Nazi interests. Despite any rumours, the British Foreign Office issued a statement that the Duke's loyalty was never questioned during the war.

Occupation policy

If Operation Sea Lion had been successful, the Einsatzgruppe under Franz Six would have been involved in establishing the New European Order. Six's headquarters were to be in London, with sub-offices in Birmingham, Liverpool, Manchester and Edinburgh. Six's forces were to receive a blacklist ('Sonderfahndungsliste G.B.') of 2,820 people to be arrested as a matter of urgency. The Einsatzgruppen was also tasked with liquidating the estimated 300,000 British Jews. Six was also given the task of securing the results of aero-technological research, technical-scientific equipment of great importance and "Germanic works of art". There were rumours that Six had made plans to move Nelson's Column to Berlin.

The RSHA has made plans to take control of the Ministry of Information, close the main news agencies and take control of newspapers. Newspapers that took an anti-German stance were to be closed immediately.

Apparently, given German security plans, the military occupation was to be temporary, and there were a number of plans for the period that would follow.


German documents in the hands of the Allies show that Walther von Brauchitsch had ordered the entire male population between the ages of 17 and 45 to be interned in camps and then shipped to the continent, barring exceptional circumstances. Such a measure would have affected about 25% of the male population.

The United Kingdom was to be stripped of anything of financial, military, industrial or cultural value, and the remaining population was to be subjected to a regime of terror. Civilian hostages were to be taken to ensure the safety of the occupiers, and the death penalty was to be imposed on those who showed the slightest resistance.

The deported male population was most likely to be used as industrial slaves in various regions of the Reich. Although it would have been expected that the British deportees would have been treated less brutally than the Eastern European scalves (whom the Nazis considered subhuman, fit only for work or death), the working and living conditions would have been very harsh.

One of the Reich Ministry officials for the Occupied Eastern Territories, Otto Bräutigam, claimed to have had the opportunity to read a report by General Eduard Wagner of a discussion with Heinrich Himmler in which the latter expressed his intention to use SS special forces to physically eliminate about 80% of the population of France and England after the final German victory. There is testimony that Hitler called the working class English "racially inferior".

Order of battle - Company Sea Lion (Sealion)


  1. Operation Sea Lion
  2. Operațiunea Leul de Mare
  3. ^ Cruickshank, Dan. "The German Threat to Britain in World War Two". BBC History. Archived from the original on 15 May 2017. Retrieved 7 May 2017.
  4. ^ "BBC – WW2 People's War – A Last Appeal to Reason by Adolf Hitler".
  5. ^ Deighton 1996, pp. 23–26.
  6. ^ David Shears, "Hitler’s D-Day", MHQ, vol. 6 Number 4 (Summer 1994)
  7. Hermann Göring, de opperbevelhebber van de Luftwaffe zei op 2 september 1940 tegen Kurt Student, bevelhebber van de luchtlandingstroepen: "De Führer wil helemaal niet naar Engeland, Student!“
  8. Walter Ansel, Hitler Confronts England, Duke University Press, 1960
  9. 2,0 2,1 2,2 2,3 2,4 2,5 Ρεϊμόν Καρτιέ, Ιστορία του Β' Παγκοσμίου Πολέμου, Πάπυρος, Αθήνα, 1964

Please Disable Ddblocker

We are sorry, but it looks like you have an dblocker enabled.

Our only way to maintain this website is by serving a minimum ammount of ads

Please disable your adblocker in order to continue.

Dafato needs your help!

Dafato is a non-profit website that aims to record and present historical events without bias.

The continuous and uninterrupted operation of the site relies on donations from generous readers like you.

Your donation, no matter the size will help to continue providing articles to readers like you.

Will you consider making a donation today?