Author's Note: This article is designed only as a short introduction to the topic of Operation Sealion. At some stage, the author intends to write a much more detailed series of articles about this plan, as well as the plans for British defence against such an invasion and the plans for resistance in the event of occupation.
This year (2010) marks the 70th anniversary of the Battle of Britain, the gallant struggle of the RAF's Fighter Command against the might of the German Luftwaffe.(1) While a major campaign in itself and the subject of numerous books, articles, webpages and even a major motion picture, this attempt by the Luftwaffe to attain air superiority over Great Britain by defeating the RAF, which became known as the Battle of Britain, was in fact fought as the main prerequisite for the planned German invasion of Britain, codenamed Operation SEALION and originally scheduled for September 1940. The evacuation of the BEF from Dunkirk had left the Wehrmacht in control of the Channel Coast after the fall of France and while this was an enviable position to be in, it meant that the Germans were now forced to contemplate what to do about what the Chief of Luftwaffe Intelligence called 'the most dangerous enemy'. The dire state of the British Army after the evacuation from the continent demanded immediate attention and while it would take time for reorganise and re-equip the ground forces available; they could only get stronger as time went on. Arguments still rage to this day as to how serious Hitler actually was, in contemplating an amphibious invasion of Britain, but whatever the case, the preparations that were made were conducted in a serious manner and involved a considerable cost to the German war effort. Whatever their actual chances of success, the landings were planned as a contingency and were dependent on the efforts of the Luftwaffe to achieve air superiority over the landing area and much of southern Britain, in order to forestall both the RAF and Royal Navy intervening in the operation.
OKW (Oberkommando der Wehrmacht or High Command of the Armed Forces) was the main strategy-making body and was headed by Hitler, with Generals Keitel and Jodl alongside. To this reported the high commands of the various services, the OKH (Oberkommando des Heeres - Army High Command under Generalfeldmarschall von Brauchitsch), OKM (Oberkommando der Marine - Naval High Command under Grossadmiral Raeder) and OKL (Oberkommando der Luftwaffe - Air Force High Command under Reichsmarschall Göring). See Figure 1. The timeline of events relating to Sealion is as follows:
The main planning for the operation came out of two directives from Hitler and a supplemental one from the OKW, the first of which was issued on 16 July 1940. As mention above, up to this point, various meetings had occurred and planning documents had been issued by all three services and their High Commands, including a memo from Jodl dated 12 July 1940 which alluded to the operation being called Löwe (Lion) and being a broad front operation, not much more complex than an extended river crossing. While the Heer found the idea appealing, rivers are not tidal, are not subject to severe weather and don't have the enemy's Home Fleet in a position to contest the crossing. Following this was a meeting between Hitler, von Brauchitsch, and General der Artillerie Franz Halder (the Army Chief of Staff) on 13 July 1940, where Halder presented more detailed planning proposals that outlined an operation incorporating 39 divisions and around 500,000 men (published 20 July). Hitler authorised continued preparations but was puzzled over the lack of peace feelers from Britain, as he once again outlined that he would prefer a negotiated settlement as he did not wish to hand Britain a military defeat which would disrupt the empire and only be of benefit to Japan and the USA. Hitler also reviewed his decision to reduce the size of the army by thirty-five divisions to release additional manpower for the economy and scaled it down to a reduction of fifteen divisions.
Fuhrer Directive No. 16 issued on 16 July 1940 stated that the Wehrmacht would 'begin preparations for, and if necessary carry out, an invasion of England. The aim of this operation is to eliminate Great Britain as a base of operations from which the war against Germany can be fought and, if necessary, the island will be completely occupied.' An invasion would be carried out on a broad front and preparations completed by mid-August. The Luftwaffe would eliminate the RAF as an effective fighting force and interdict the Royal Navy should it try to intervene and the Kriegsmarine would furnish an invasion fleet and protect it. Current army plans would form the basis of the operation, although the line would be shortened slightly to between Ramsgate and the Isle of Wight. Hitler also confirmed that the operation would be codenamed Seelöwe (Sealion). In some ways, it seemed that the Luftwaffe was expected to almost defeat Britain by itself. Goring and his commanders however, mostly ignored the directive and continued with their own plans - they thought an invasion was going to be unnecessary anyway, while Raeder and the Kriegsmarine thought that OKW was insane. From this point, the Heer continued to be the main supporter of the plan, with the Luftwaffe lukewarm to the idea and the Kriegsmarine trying to torpedo the Heer's plan.
Following Fuhrer Directive No. 16, in which many historians highlight the words 'and if necessary carry out, an invasion' as an indication of Hitler's lack of commitment, the second half of July was filled with various staff meetings and proposals where the Luftwaffe confirmed it would be able to start a major air campaign against the RAF in early August but the Kriegsmarine would not be able to complete its preparations until mid-September. On 28 July 1940, they proposed that if the invasion were to go ahead that a beachhead be established near Dover, the closest point to the continent, where a narrow corridor could be protected by minefields to each side as well as groups of U-Boats and E-Boats beyond these. The Kriegsmarine estimated it would take ten days to put the first wave ashore and needless to say, the Heer was horrified. It had wanted landings all along the south coast from Folkestone to
Brighton with a separate landing from Cherbourg. It wanted wheeled and tracked vehicles and so all the car ferries were to be used along with all the cross-channel tourist facilities. The first wave was to be landed over three to four days and consist of 260,000 men, 30,000 vehicles and 60,000 horses. This was followed by a memo dated 31 July 1940, which advised that given the Kriegsmarine's preparations were complete by 15 September 1940, the dates most suitable for invasion would be from 22 - 26 September, when the weather was often bad. It could not however, guarantee to able to protect the invasion from the Royal Navy and would not be able to guarantee resupply if there was indeed bad weather. It was suggested that the invasion was put off until May 1941 when additional surface assets would be available and additional work be able to be carried out on converting or building vessels to allow for amphibious operations.
Fuhrer Directive No. 17 was issued on 1 August 1940 (followed by one from OKW) and ordered the intensification of the air campaign against the RAF, targeting their air units, ground installations, observation facilities and aircraft factories. It also stated that all preparations for invasion would be completed by 15 September 1940, the original deadline being kept as Hitler was concerned over the strength of the British Army if the invasion was postponed until the following spring. Despite misgivings, the Kriegsmarine continued to scour the waterways
of occupied Europe for suitable craft, both powered and unpowered and proceeded to convert many of them by adding drop-down ramps, while the Heer conducted energetic landing exercises, with propaganda film crews in attendance. Mid-September saw the Kriegsmarine complete its assembly of the vessels to be used in the initial lift, as well as the finalisation of the German forces to be used (see Figures 2 and 3), the assault routes to be taken (see Figures 4 and 7), as well as the plans for occupation (see Figures 5 and 6).
Needless to say, the Luftwaffe’s defeat in the Battle of Britain forced Hitler to postpone the invasion on 17 September 1940 and then on 12 October 1940 postpone it until the following year. In any case, by then, Hitler’s attention had moved eastwards and was focused on his main ideological opponent, the USSR, with planning and preparations being undertaken for Operation Barbarossa.
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Films / TV Documentaries / Docu-dramas
'The Post Mistress who was a Spy?', part of the History Mysteries series, 24 January 2006 at 3pm, BBC2 / Open University. Series Director: Samantha Bakhurst; Series Producer: Sally Angel.
Hitler and the Invasion of Britain, BBC2, aired on 07/04/1998, 50mins, part of the Timewatch series.
Hitler's Britain, Channel 5, Part One: 03/12/02, 60mins; Part Two: 10/12/02, 60mins.
Invasion, BBC2, Presenter: Dan Cruikshank. Three episodes aired between 28/10/2001 and 11/11/2001.
It Happened Here (1964), Directors: Kevin Brownlow / Andrew Mollo, 97mins, English/German, B&W, ASIN: B000CBOZWG, Studio: Film First.
The Real Dad's Army (2009), Channel 4, Part One: 10/01/09, 60mins; Part Two: 17/01/09, 60mins; Part Three: 24/01/09, 60mins. Note: There was another series entitled The Real Dad's Army, the fourth episode of which was hosted by Ian Lavender and was about the Auxiliary Units.
When Hitler Invaded Britain, ITV1, 04 July 2004, 22.15 – 23.45, 90 mins.
For those wanting to fight Operation Sealion, there are number of possibilities. For board wargamers, the US wargame manufacturer, SPI, produced a wargame entitled Seelöwe, designed by John Young and published in 1974, which only covered the ground campaign, assuming the Luftwaffe had decisively defeated the RAF and were in a position to block any Royal Navy intervention. The game also had a modified edition produced in the UK by SPI (UK) Ltd that had a colour map with greater detail. XTR produced a game called Operation Sealion by L. Dean Webb that was included in the magazine Command, issue number 45, published in October 1997. 3W also pitched in with a wargame entitled Fight on the Beaches by Roger Sandell and John Lambshead that accompanied The Wargamer magazine, Issue 40, published in April 1985. GMT Games of Hanford, CA produced a game in 1994 entitled Britain Stands Alone, designed by Jim Werbaneth. This covers the entire land-air-sea campaign for Operation Sealion and so is somewhat more complicated and time-consuming than Seelöwe, but the players can decide on their own strategy for the operation with the full ground, naval and air forces at their command. GDW produced a game entitled Their Finest Hour in 1982 that was designed by Jim Astell and part of the enormous Europa series of games (being volume five) that simulated World War II at the divisional level. Part of the game simulated the forces that would have been involved in Operation Sealion had the Luftwaffe won the Battle of Britain, which is in fact the main focus. There was also a wargame entitled Sea Lion from Wargaming Enterprises, designed by Mark Jumper produced in 1970 and I have seen a custom designed and built expansion for the Axis & Allies series of games entitled 'Operation: Sealion' from a company called Rune Blade Studios on eBay. There is also likely to be a future edition of the Strategy & Tactics magazine with a game devoted to the subject (see https://strategyandtacticspress.com/ for details of up-and-coming issues) and I’ve seen a Sealion related scenario for the game Memoir ‘44. For additional wargaming material, there is also Issue 13 of Ragnarok (the journal of fantasy and science fiction wargaming) and Issues 29, 30 and 56 of The Journal of the Society of Twentieth Century Wargamers. Any decent miniature wargame rules (such as Rapid Fire) should have the rules and order of battle coverage for someone to put together a Sealion scenario with a little work – in saying that, there is a specific supplement entitled 'Operation Sea Lion' produced by The Two Fat Lardies (http://www.toofatlardies.co.uk) for their 20mm wargames rules system I Ain't Been Shot Mum.
As far as PC wargaming is concerned, the official expansion pack for Talonsoft's West Front focused on Operation Sealion, and games such as Steel Panthers: World at War (Matrix Games), Steel Panthers for Windows – World War 2 (The Camo Workshop), Combat Mission (CDV) and Operational Art of War (Talonsoft) often have mission editors where you can build your own scenarios. There is even an extra map for Battlefield 1942 entitled 'Operation Sealion', which is just over 15Mb in size, from Bumsoft, and can be downloaded from the Filefront website at http://battlefield1942.filefront.com/file/Operation_Sea_Lion;35707.
For other ‘what-if’ operations by German forces during World War II, Avalon Hill’s 1977 game, Air Assault on Crete, designed by Randell C Reed and Vance von Borries has two such elements. The first is that a second game was included in the official Avalon Hill release that covers Operation Hercules, the proposed joint German – Italian invasion of Malta in 1942. There are also specific scenarios on Operation Hercules in Talonsoft's Operational Art of War and Conquest of the Aegean (third in the Airborne Assault series) from Panther Games, with an option to create your own scenarios in Combat Mission 3: Afrika Korps from CDV. Secondly, a scenario variation was included in Volume 18, No. 3 of The General, Avalon Hill’s wargaming magazine with its own board and counters that covered a possible parachute assault on Cyprus. There was also a boardgame entitled Operation Felix that was included with Strategy & Tactics magazine, Number 153 (1992) and looked at the planned German assault on Gibraltar in either 1940 or 1941.
(1) See for example http://www.telegraph.co.uk/news/newstopics/world-war-2/battle-of-britain/8012065/Battle-of-Britain-service-Prince-Charles-and-Prince-William-lead-tributes-to-The-Few.html.