Operation Sealion: The Planned German Invasion of Britain  

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Operation Sealion was the name given by Hitler for the planned invasion of Great Britain in 1940. Thankfully it was never carried out as the Germans lost the Battle of Britain and Hitler was more interested in the forthcoming attack on Russia as opposed to invading Britain. The projected invasion on Britain included: 6 divisions invading Kent via the areas near Ramsgate, Folkstone and Bexhill. 4 divisions invading Sussex and Hampshire via the area around Brighton and the Isle of Wight and 3 divisions invading Dorset via Lyme Bay. From Kent they would advance to south-east London and then to Malden and St. Albans north of London. From Sussex/Hampshire, they would advance to the west of London and meet up with the other 6 divisions thus encircling London. Other parts of the group would head towards Gloucester and the River Severn region. The whole plan relied on Germany having complete control of the English Channel, which, in turn meant that Germany had to have control of the skies so that the Royal Air Force could not attack German ships crossing the Channel. Hence victory in the Battle of Britain was an integral part of the plan. Operation Sealion looked simple in theory. Britain should have been an easy target. The Luftwaffe was very experienced in modern warfare, the Wehrmacht had experienced astonishing success since the attack on Poland and the British had lost a vast amount of military hardware on the beaches of Dunkirk. It is said that Hitler was prepared to offer Britain generous peace terms. However, on May 21st, 1940, Admiral Raeder told Hitler about a plan to invade Britain and Hitler, it is said, was taken in by the plan. If Britain had not surrendered, Hitler had planned an economic war which could have taken a long time to be effective. However, a military conquest of Britain would be swift and decisive. The military success of the German military since September 1939, seemed to confirm in Hitler’s mind that an attack on a demoralised British Army would be swift. Towards the end of June 1940, Hitler gave the order for the German military to make plans for an invasion of Britain. The German Navy detailed many problems that would be experienced for either a short or a long crossing. In December 1939, the Wehrmacht had produced its own report. This favoured a surprise attack on Britain via East Anglia by 16 or 17 divisions.

It was only when it became clear that Britain would not sign peace terms that Hitler gave his backing to an invasion. On July 2nd 1940, Hitler gave his first tentative orders regarding a possible invasion of Britain. It stated that "a landing in England is possible, providing that air superiority can be attained and certain other necessary conditions fulfilled.....all the preparations must be made on the basis that the invasion is still only a plan, and has not yet been decided upon." Hitler, July 2nd 1940. Around this time the Auxiliary Units were being formed in Whitehall. On July 13th, the German army chiefs presented their plan to Hitler. They were so confident of success that they believed that Britain would be occupied within a month. Hitler wanted Sea Lion to be over by mid-September. One of the interesting issues to come out of this episode was the inability of the three units that made up the German military to either work together or support one another. Another key point that came out of this episode in the war, was Hitler's seeming refusal to listen to his military commanders and wanting things done his way. This came out of the success the military had against Poland and the nations of Western Europe - countries attacked without the overwhelming support of the military but attacked because Hitler instinctively knew that they would win - or so he believed.

OPERATION SEALION By CART member Peter D Antill BA (Hons). MSc (Econ). PGCE (PCE).

See Peter's other article on Small Arms and Support Weapons of the Wehrmacht here.

A Primer and List of Sources (Bottom of page)

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. 

Introduction 

This year 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. 

Timeline 

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 above. The timeline of events relating to Sealion is as follows: 

·          Up until November 1939 – No serious consideration was given by Hitler or the German OKW to an invasion of the British Isles. The main focus of any operations would be an air and naval blockade to 'encourage' negotiations. 

·          November 1939 – Both OKM and OKH conduct separate studies as to the feasibility of an amphibious landing. 

·          January 1940 – Grossadmiral Erich Raeder responds to the OKH study (codenamed North West) by pointing out the many difficulties and obstacles to such an operation. Both Raeder and Hitler still prefer the option of an air and naval blockade. 

·          21 May 1940 – Raeder quizzes Hitler as to the possibility of an amphibious landing and receives a negative response. Despite this, OKM continues to study the problem and recommends a cross-channel route rather than a North Sea one. 

·          10 July 1940 – Battle of Britain begins. 

·          16 July 1940 – Hitler issues Fuhrer Directive No. 16. This states "I have decided to prepare a landing operation against England, and if necessary, to carry it out. The aim of this operation will be to eliminate the English homeland as a base for the prosecution of the war against Germany" and makes it clear that the Heer plan will form the basis for moving forward. 

·          20 July 1940 – OKH publishes its 'broad front' plan, detailing a landing across a 237-mile front from the Thames Estuary to LymeBay. Raeder rejects it as the Navy lack the resources to support a lift of that magnitude. 

·          21 August 1940 – OKH submit a scaled down plan that details a landing by ten divisions over four days between Ramsgate and Brighton (100 miles). Raeder amends this plan further to a landing of nine divisions over four days across a front of ninety miles. The lead elements from Strauss' 9th Army and Busch's 16th Army would come ashore between Folkestone and Brighton, supported by the 7th Flieger and 22nd Luftlande Divisions, as well as 250 amphibious tanks. 

·          Mid-September 1940 – The Kriegsmarine finishes assembling the shipping to be used in the operation. 

·          26 – 27 September 1940 – Most likely landing dates given the Heer's demand for dawn landings on an ebbing tide and the Navy's requirement for partial moonlight during transit. 

German Plans 

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 mentioned 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 also 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, the assault routes to be taken, as well as the plans for occupation. 

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. 

List of Sources

Articles 

Boylan, Kevin. 'Historical Commentary' in the playbook for Britain Stands Alone, GMT Games, HanfordC.A., 1994. 

Campbell, John P. ‘A British Plan to Invade England, 1941’ in The Journal of Military History, Vol. 58, No. 4, October 1994, pp. 663 – 684. 

Crawford, John. 'The Navy Lark!' in The Journal, Spring 2007, Issue 57, pp. 26 – 32. 

Davis, Frank. ‘Sea Lion: The German Plan to Invade Britain, 1940’ in Bartlett, M. Assault from the Sea, Naval Institute Press, Annapolis, 1983, pp. 228 – 235. 

Davis, Frank. 'Seelöwe: The German Plan to Invade Britain, 1940' in Strategy and Tactics, No. 40, September / October 1973, pp. 20 – 33. 

Elstein, David. ‘Operation Sealion: The Plan to Invade Britain’ in History of the Second World War, Volume 1, Number 11, pp. 300 – 308. 

Leonidov, A. 'The Fate That Was In Store For Britain' in International affairs, Number 6, Volume 6 (1960), pp. 65 – 71. 

Lofthouse, Michael. 'British Order of Battle, 30th September 1940' in The Journal, Winter 2006, Issue 56, pp. 8 – 12. 

Macksey. Kenneth. ‘Would Britain have Resisted?’ in World War II Investigator, October 1988, pp. 7 – 11. 

Plehwe, Friedrich-Karl von. ‘Operation Sealion 1940’ in Royal United Services Institute Journal, March 1973, pp. 47 – 53. 

Ray, Christopher. '1940 – 41 Britain's Finest Hour or Hitler's Greatest Hoax?' in History Review, March 1997, Issue 27, pp. 33 – 37. 

Sandell, Roger and Lambshead, John. 'Invasions and Invaders' in The Wargamer, Number 40, April 1985, pp. 6 – 10. 

Schenk, Dr Peter. ‘Sealion – The Invasion That Never Was’ in After the Battle, No. 69, pp. 1 – 19. 

Smith, S C. 'Operation Sealion – 1940, Part 1 – Assault Vessels' in The Journal, Spring 1998, Issue 29, pp. 84 – 88. 

Smith, S C. 'Operation Sealion – 1940, Part 2 – Wargames Scenarios' in The Journal, Summer 1998, Issue 30, pp. 56 – 62. 

Tucker, Anthony. 'Operation Sealion: Myth or Reality?' in Wargames Illustrated, February 1989 to April 1989. 

Werbaneth, James P. 'Operation Sea Lion: England's Final Hour?' in Command magazine, Issue 45, October 1997, pp. 42 – 59. 

Wills, Henry. ‘British Invasion Defences’ in Ramsey, Winston G. (Ed) After the Battle, Number 14, 1976, pp. 38 – 46. 

Wise, Terry. 'Operation Sealion' - a series of articles in Airfix Magazine from June 1975 to May 1976. These were: 'Operation Sealion – The Non-Invasion', June 1975, Vol 16, No. 10; 'Operation Sealion – British Forces', July 1975, Vol 16, No. 11; 'Operation Sealion - Dad's Army', August 1975, Vol 16, No. 12; 'Operation Sealion - German Plans', September 1975, Vol 17, No. 1; 'Operation Sealion - German Forces', October 1975, Vol 17, No. 2; 'Operation Sealion - Wargaming', November 1975, Vol 17, No. 3; 'Operation Sealion - Wargaming (cont)', December 1975, Vol 17, No. 4; 'Operation Sealion as a Wargame - Nautical Models', January 1976, Vol 17, No. 5; 'Operation Sealion as a Wargame', April 1976, Vol 17, No. 8; 'Operation Sealion as a Wargame', May 1976, Vol 17, No. 9. 

Books - See many of these in our shop. 

Alexander, Colin. Ironsides Line: The Definitive Guide to the General Headquarters Line Planned for Great Britain in Response to the Threat of German Invasion 1940-1942, Historic Military Press, Storrington, 1999. 

Angell, Stewart. The Secret Sussex Resistance, Middleton Press, Midhurst, 1996. 

Ansel, Walter. Hitler Confronts England, Duke University Press, Durham, N.C., 1960. 

Bird, Christopher. Silent Sentinels: The Story of Norfolk's Fixed Defences during the Twentieth Century, Larks Press, Dereham, 2001 (reprint). 

Bodleian Library. German Invasion Plans for the British Isles 1940, University of Oxford, Oxford, 2007. 

Brayley, Martin. The British Army 1939 – 45 (1) North-West Europe, Osprey Publishing Ltd, Oxford, 2001, Men-at-Arms Series No. 354. 

Burridge, David. 20th Century Defences in Britain: Kent, Brassey's, 1997. 

Butler, Chris. East Sussex Under Attack, The History Press, Stroud, 2007. 

Butler, Chris. West Sussex Under Attack, The History Press, Stroud, 2008. 

Carvell, Steve. Twentieth Century Defences in Warwickshire, Tempus Publishing, Stroud, 2007. 

Clarke, Comer. England Under Hitler, New English Library, London, 1972. 

Cocks, A E. Churchill's Secret Army 1939 – 45 and Other Recollections, The Book Guild Ltd, Lewes, 1992. 

Collier, Basil. Defence of the United Kingdom, History of the Second World War: United Kingdom Military Series, Naval & Military Press Ltd, Uckfield, 2006. 

Cruikshank, D. Invasion: Defending Britain from Attack, Boxtree, London, 2001. 

Deighton, Len. Blitzkrieg, Granada, London, 1981. 

Evans, Martin M & McGeoch, Angus. Invasion: Operation Sealion 1940, Longman, London, 2004. 

Fleming, Peter. Invasion 1940, Rupert Hart-Davis, London, 1957. 

Foot, William. Beaches, Fields, Streets and Hills, Council for British Archaeology, York, 2006. 

Foot, William. Defended England 1940: The South-West, Midlands and North, Tempus Publishing, Stroud, 2008. 

Foot, William. The Battlefields That Nearly Were, Tempus Publishing, Stroud, 2006. 

Forty, George. British Army Handbook 1939 – 1945, Sutton Publishing, Stroud, 2002. 

Foster, Joe. The Guns of the North-East: Coastal Defences from the Tyne to the Humber, Pen & Sword, Barnsley, 2004. 

Gilbert, Adrian. Britain Invaded: Hitler’s Plans for Britain – A Documentary Reconstruction, Century, London, 1990. 

Gillies, Midge. Waiting for Hitler – Voices from Britain on the Brink of Invasion, Hodder & Stoughton, London, 2006. 

Glover, Michael. Invasion Scare – 1940, Pen & Sword Books, Barnsley, 1990. 

Green, Major M. Warwalks: Stop Line Green, Reardon Publishing, Leckhampton, 1999. 

Grinell-Milne, Duncan. The Silent Victory – September 1940, London, 1954. 

Hayward, James. The Bodies on the Beach, CD41 Publishing, Dereham, 2001. 

Hewitt, Geoff. Hitler's Armada – The Royal Navy and the Defence of Great Britain, April – October 1940, Pen & Sword Maritime Books, Barnsley, 2008. 

Kieser, Egbert. Hitler on the Doorstep – Operation Sealion: The German Plan to Invade Britain 1940, Arms and Armour Press, London, 1997. 

Klee, Karl. Unternehmen Seelowe, 2 Volumes, Musterschmit-Verlag, Gottingen, 1958 & 1959. 

Lampe, David. The Last Ditch, G P PutnamSons, New York, 1968. This has now been republished with a forward from Gary Sheffield by Greenhill Books, London in February 2007. 

Lavery, Brian. We Shall Fight Them on the Beaches: Defying Napoleon and Hitler 1805 and 1940, US Naval Institute Press, Annapolis, MD, 2009. 

Longmate, Norman. If Britain Had Fallen, BBC / Hutchinson, London, 1972. 

Longmate, Norman. Island Fortress: The Defence of Great Britain 1603 – 1945, 

Longmate, Norman. The Real Dad's Army, Arrow, 1974. 

Lowry, Bernard. 20th Century Defences in Britain – An Introductory Guide, Council for British Archaeology, 1995. 

Lowry, Bernard. British Home Defences 1940 – 45, Osprey Publishing, Oxford, 2004, Fortress Series No. 20. 

Lowry, Bernard. Discovering Fortifications from the Tudors to the Cold War, Shire Publications Ltd, 2006. 

Lucas, James. German Army Handbook 1939 – 1945, Sutton Publishing, Stroud, 2002. 

McCutcheon, Campbell. (Ed) Home Guard Manual 1941, Tempus Publishing, Stroud, 2007. 

McLynn, F. Invasion: From the Armada to Hitler 1588 – 1945, Routledge & Kegan Paul, London, 1987. 

MLRS Books. The Role of the Luftwaffe in Operation Sealion, MLRS Books, Buxton, 2006. 

Osborne, Mike. 20th Century Defences in Britain: Cambridgeshire, Concrete Publications, Market Deeping, 2001. 

Osborne, Mike. 20th Century Defences in Britain: The London Area, Concrete Publications, Market Deeping, 2006. 

Osborne, Mike. Defending Britain: Twentieth Century Military Structures in the Landscape, Tempus Publishing, Stroud, 2004. 

Osborne, Mike. Pillboxes of Britain and Ireland, Tempus Publishing, Stroud, 2008. 

Necker, Wilhelm. Hitler's War Machine and the Invasion of Britain, Lindsay Drummond, London, 1941. 

Robinson, Derek. Invasion, 1940: The Truth about the Battle of Britain and What Stopped Hitler, Constable, London, 2005. 

Saunders, A J. English Heritage Book of the Channel Defences, B T Batsford, London, 1997. 

Saunders, Ian. Pillboxes: Images of an Unfought Battle, Lulu Press Inc., Morrisville, NC, 2005. 

Schellenburg, SS General Walter (with an introduction by Prof. John Erikson). Invasion 1940, St Ermin’s Press, London, 2001. 

Schenk, Peter. Invasion of England 1940: The Planning of Operation Sealion, Conway Maritime Press, London, 1990. 

Sheers, Owen. 'Guerrillas in Waiting' in The Guardian, 20 October 2007, also located at http://www.guardian.co.uk/lifeandstyle/2007/oct/20/weekend.owensheers as of 02 October 2009. 

Taylor, Telford. The Breaking Wave: The German Defeat in the Summer of 1940, Weidenfeld & Nicolson, London, 1967. 

Taylor, Telford. The March of Conquest: The German Victories in Western Europe, Edward Hulton, London, 1959. 

Thomas, Nigel. The German Army 1939 – 45 (1) Blitzkrieg, Osprey Publishing Ltd, Oxford, 1997, Men-at-Arms Series No. 311. 

Ward, Arthur. Resisting the Nazi Invader, Constable & Co, London, 1997. 

Warner, Philip. Invasion Road, Cassell Ltd, London, 1980. 

Warwicker, John. Churchill’s Underground Army, Frontline Books, Barnsley, 2008. 

Warwicker, John. With Britain in Mortal Danger, Cerberus Publishing, Bristol, 2002. 

Wilks, Mick. The Defence of Worcestershire and the Southern Approaches to Birmingham in World War II, Logaston Press, Little Logaston, 2007. 

Williamson, Alan. East Ridings Secret Resistance, Middleton Press, Midhurst, 2004. 

Wills, Henry. Pillboxes: A Study of UK Defences 1940, Leo Cooper / Secker and Warburg, 1985. 

Wilmot, Chester. The Struggle for Europe, Collins, 1952. 

Wheatley, Ronald. Operation Sealion, OxfordUniversity Press, London, 1958. 

Chapters in Edited Books 

Badsey, Stephen. 'Disaster at Dunkirk: The Defeat of Britain, 1940' in Tsouras, Peter G. (Ed) Third Reich Victorious, Greenhill Books, London, 2002. 

Macksey, Kenneth. 'OperationSea Lion: Germany Invades Britain, 1940' in Macksey, Kenneth. The Hitler Options: Alternate Decisions of World War II, Greenhill Books, London, 1995. 

Roberts, Andrew and Ferguson, Niall. ‘Hitler’s England: What If Germany had Invaded Britain in May 1940?’ in Ferguson, Niall (Ed). Virtual History: Alternatives and Counterfactuals, Picador, London, 1997. 

Wallach, Jehuda L. 'The Sea Lion That Did Not Roar: OperationSea Lion and its Limitations' in Hattendorf John B and Murfett, Malcolm H. The Limitations of Military Power, MacMillan, London 1990, pp. 173 – 202. 

Internet Resources 

Axis History Factbook. Order of Battle – Unternehmen Seelowe (Sealion) Webpage located at http://www.axishistory.com/index.php?id=1145 as of 08 January 2007. 

Barrett, Steve. Steve Barrett Books Website detailing historical information about Operation Sealion as well as the opportunity to buy a copy of the author's own alternate history novel regarding the operation, entitled 'Sealion'. Located at http://www.stevebarrettbooks.com/index.htm, active as of 16 January 2005. 

BritishResistanceMuseum. The Museum of the British Resistance Organisation, located at http://www.parhamairfieldmuseum.co.uk/brohome.html as of 18 August 2009. Museum is located at Parham Airfield, Framlingham, Suffolk. 

Carter, Tim. Pillboxes web page at http://www.geocities.com/pentagon/camp/3224/ as of 04 June 2998. 

Cruikshank, Dan. The German Threat to Britain in World War Two Webpage, at http://www.bbc.co.uk/history/worldwars/wwtwo/invasion_ww2_01.shtml  , part of the BBC History Website, 30 January 2007. 

Defence of Britain Project homepage, currently located at http://www.britarch.ac.uk/projects/dob/ as of 15 May 2008. 

Farrant, David. WW2 & Cold War History in Britain website, currently located at http://www.century20war.co.uk/ as of 04 June 2008. 

Flin, David and Brooks, Alison. Why Sealion is not an option for Hitler to win the war webpage, currently located at http://www.flin.demon.co.uk/althist/seal1.htm, as of 08 January 2007. 

History Learning Site. Operation Sealion Webpage located at http://www.historylearningsite.co.uk/operation_sealion.htm, active as of 16 January 2005. 

Montgomerie, Ian. Why Operation Sealion Wouldn't Work webpage, currently located at http://gateway.alternatehistory.com/essays/Sealion.html, as of 08 January 2007. 

Parker, Larry. 'Sea Lion vs. Overlord' webpage, Military History Online website at http://www.militaryhistoryonline.com/wwii/articles/sealionvsoverlord.aspx   as of 08 January 2007. 

Pillbox Study Group website, currently located at http://www.pillbox-study-group.org.uk/ as of 04 June 2008. 

Saunders, Ian. World War 2 Pillboxes and Invasion Defences in the UK Website, currently located at http://www.pillboxesuk.co.uk, active as of 4 September 2005. 

Simon Wiesenthal Centre. Operation Sealion Webpage currently located at
http://motlc.wiesenthal.com/text/x20/xm2033.html and active as of 17 January 2005. 

Spartacus Schoolnet. Operation Sealion Webpage, located at http://www.spartacus.schoolnet.co.uk/2WWsealoin.htm, active as of 16 January 2005. 

Stone & Stone Website has a bibliography page listing a number of books, located at
http://books.stonebooks.com/cgi-bin/foxweb.exe/base/subjects?1000167  , active as of 17 January 2005. 

Sykes, Tom. Coleshill House - Home of Churchill's Underground Army Website, located at http://www.coleshillhouse.com/ as of 18 August 2009 (Coleshill Auxiliary Research Team). 

Waller, David. Auxiliary Unit News Website, located at http://www.auxunit.org.uk/ as of 18 August 2009. 

Wikipedia. British Anti-Invasion Preparations of World War II Webpage, currently at http://en.wikipedia.org/wiki/British_anti-invasion_preparations_of_World_War_II as of 25 March 2007. 

Wikipedia. Operation Sealion Webpage, currently located (as of 22 January 2007) at http://en.wikipedia.org/wiki/Operation_Sealion. 

Monographs 

Calendar 1937 – Booklet detailing sabotage and guerrilla warfare techniques. 

Calendar 1938 – Booklet detailing sabotage and guerrilla warfare techniques. 

Dawes, Maj E J M. Defeating Organised Resistance Networks: Are There Lessons In History?, Defence Research Paper, Advanced Command and Staff Course No. 7, Joint Services Command and Staff College, September 2003 – July 2004. 

Grylls, Ch. Off. C F. What Factors Led to Hitler's Decision not to Invade Britain in 1940 Despite his Military Success?, Defence Research Paper, Advanced Command and Staff Course No. 10, Joint Command and Staff College, September 2007 – July 2007. 

Gubbins, Col Colin M. Partisan Leader's Handbook: Principles of Guerilla Warfare and Sabotage. Booklet detailing sabotage and guerrilla warfare techniques. 

Gubbins, Col Colin M. The Art of Guerilla Warfare. Booklet detailing sabotage and guerrilla warfare techniques. 

Maskell, Maj A J. Let Us Go Forward Together: How Did the Political and Military Strategic Environment in 1940 Influence Planning for the Defence of the United Kingdom?, Defence Research Paper, Advanced Command and Staff Course No. 9, Joint Services Command and Staff College, September 2005 – July 2006. 

Olson, Greg D. McCanne, Randy & Teicher, DarioE.OperationSea Lion: A
Joint Critical Analysis. JointForcesStaffCollege, NationalDefence
University, Norfolk, VA, 2002 (available at http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA421637&Location=U2&doc=GetTRDoc.pdf  ). 

Ruddy, Austin J. British Anti-Invasion Defences 1940 – 1945, Historic Military Press, Pulborough, 2003. 

Taylor, Andy (Ed) Auxiliary Units: History and Achievement 1940 – 1944, Gripping Press, Needham Market, 1998. From an original document by Major N V Oxenden MC, written in October 1944 and discovered by the BritishResistanceOrganisationMuseum, Parham Airfield, Framlingham, Suffolk. 

Highworth & Co. The Countryman's Diary 1939 (Highworth's Fertilisers). Booklet detailing sabotage and guerrilla warfare techniques. 

Warren. Derrick. Now You See It – Then You Didn’t! Inter-Channel Stop Line, Somerset Industrial Archaeological Society, SIAS Survey No. 14, 2000, ISBN: 0953353931. 

Novels 

Cox, Richard. Sealion, Futura Publications, London, 1977. 

Deignton, Len. SS-GB, Triad Grafton, London, 1986 (Reprint). 

Macksey, Kenneth. Invasion: The German Invasion of England, July 1940, Arms and Armour Press, London, 1980. 

Stevens, Gordon. And All The King's Men, Pan Books, London, 1991. 

Thayer, James S. S-Day: A Memoir of the Invasion of England, St Martin's Press, New York, 1990. 

Official Publications 

General Staff. Notes on German Preparations for Invasion of the United Kingdom, 2nd Edition, M.I.14, WOP 9372, January 1942. 

German High Command (OKW). OKW Directives for the Invasion of UK. Operation Seelöwe (Sealion) Summer and Autumn1940, 2 July 1940 – 22 October 1940. 

Highworth & Co. The Countryman’s Diary 1939: Highworth’s Fertilizers (Cover for a General Staff training booklet to teach members of the Auxiliary Units about explosive devices), 42 pp. 

Parry, W E. (Director of Naval Intelligence) German Plans for the Invasion of England 1940 (Operation "SEALION"), NID24/GHS/1, London, February 1947. 

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. 

Endnotes 

(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  .