Operation “Sea Lion” Invading England In 1940? [Part Two]

November 14, 2016 by crew

Last week, we embarked on an exploration of Operation Sea Lion, one of the most fascinating and debated invasions that never took place in World War II. In summary, Sea Lion was the proposed German invasion of England in the late summer of 1940.


Western Europe had just been crushed in a stunning German blitzkrieg, and carrying the offensive across the English Channel to topple the United Kingdom seemed, for a brief window, to at least pose a tantalizing (and terrifying) possibility.

Obviously, this invasion never took place. The German Luftwaffe (Air Force) failed to defeat the British Royal Air Force (RAF) in the epic Battle of Britain. Without air supremacy, German prospects in any cross-channel invasion were nil.

But what if the Germans had won the Battle of Britain? They came very close, after all, and such a victory could have opened the door for a “Sea Lion” invasion as we’re exploring here. In Part One of our series, we took a quick summary overview of this operation and previewed (in broad terms) some of its prospects.


Having set the stage, however, it’s now time to actually “give the go-code” and launch this hypothetical World War II invasion of southern England. Based on factors of the time, actual German plans, and the forces that would have been involved, this is a wargamer’s view how Sea Lion could have actually happened.

S-Day: September 15th, 1940

In the predawn darkness over the shores of Sussex and Kent, the roar of surf steadily fades beneath the massed drone of hundreds of German aircraft. The date is September 15th, 1940 ... set by the German High Command as “S-Day,” the code word for the opening of Operation Sea Lion. The invasion of England is on.

Our initial two battles will be fought along the east flank of the German invasion, near the vital port town of Folkestone. First, we’ll see German glider assault troops try to take Hawkinge, a badly-damaged RAF airfield just behind Folkestone, then watch 17th Infantry Division actually hit the beach just west of this critical objective.


With the RAF largely destroyed (or driven back to airfields in the Midlands and Scotland), and their radar warning network reduced to wreckage, the British can do little to intercept the initial phases of this invasion, which is delivered not from the sea...but from the air.

One of the initial targets the Germans have selected for their airborne drops is Hawkinge Airfield, just a few miles inland from Folkestone. A glider assault force of 7th Airborne Division has been detailed with taking this former RAF field, so dozens of waiting Junkers Ju-52 transport planes can bring in larger elements of German light infantry.


Hawkinge has had an RAF airfield since World War I, and served as an important staging point during the invasion of France. During the Battle of Britain, it was eventually put out of action by heavy Luftwaffe attacks, but now it may serve as a “staging airfield” for the enemy.

German airborne units fell into three broad categories. These were “Fallschirmjäger” paratroopers, “Luftlande-Sturm” (air landing assault) glider troops, and divisions of light infantry who were simply shuttled into captured enemy airfields via waves of Ju-52 transports. Of course, those airfields (like Hawkinge) had to be taken first.


Of course, Hawkinge airfield was just one target the Germans have struck from the air on S-Day. By 05:00 hours, paratroopers of Kampfgruppe “Meindl” (containing the bulk of Fallschirmjäger Regiment 1, or “FJR 1”) have also landed at Hythe and secured crossings over the Royal Military Canal.

Taking all the bridges over this canal is crucial, since it now seals off the British ground troops holding the beaches along the Romney Marsh, the main landing zone of XIII Corps.

Meanwhile, Fallschirmjäger Regiment 2 (FJR 2) has landed north of Postling, holding crossroads against any British counterattack from the north. FJR 3 has been detailed to secure the western flank against any British counterattack mounted from Sussex, detaching one battalion to take Lympe airfield, to be used to insert 22nd Air Landing Division.


Throughout the towns and villages of Kent, fighting is heavy and confused throughout these morning hours. The major British unit in the area is 1st London Division (XII Corps, Eastern Command), a Territorial unit NOT sent to France. Thus, they never lost most of their heavy equipment at Dunkirk and so make a good account of themselves.

One particular example is along the Royal Military Canal, where Kampfgruppe “Meindl” of FJR 1 actually fails to take two bridges, bloodily repelled by the London Irish Rifles (1st London Infantry Brigade). An emergency call is made to a German “kampfgeschwader” bomber group, however, who destroys the two bridges instead.

Yet while this air strike secures the Romney-Folkestone beaches from potential British counterattack or reserves, it also means these bridges will not be available to facilitate any subsequent German breakout once XIII Corps hits the beach (17th and 35th Infantry Divisions, already landing on the assault beaches).


Almost everywhere else, however, German success is swift. Although suffering high casualties in places, objectives like Lympe airfield, Postling, and Paddington are quickly secured by fallschirmjäger paratroopers and glider assault troops. By 13:00 hours, lead elements of 22nd Air Landing Division are being deployed into the bridgehead.

And as we’ve seen in our Battlegroup skirmish game, the German detachment assigned to take Hawkinge field has been successful. Although damaged in previous weeks, engineers will soon have this field in service. Two squadrons of Messerschmitt Bf-109 fighters will be based here, part of the vital air cover for further stages of the invasion.

Beaches Of Folkestone

While glider assault troops and fallschirmjäger paratroopers were hitting vital targets overlooking the invasion beaches, the first waves of German seaborne infantry were hitting the beaches themselves. Among these, the 17th Infantry Division (XIII Corps) landed along the “Romney Marsh,” extending west from the port town of Folkestone.

As wargamers, the first thing we have to understand about these Sea Lion “beach landings” is that they wouldn’t have resembled anything at Normandy. Folkestone was no Omaha or Sword beach. There Germans have not taken two years to build a 5000-ship invasion armada, and the British have nothing like Hitler’s “Atlantic Wall.”


Rather, this is a very rushed and improvised landing force hitting a rushed and improvised beach defence. True, relics of Britain’s coastal defences can be visited even today, just bear in mind that almost all of this was built in the winter and spring of 1940-41. In September of 1940, we’re just looking at some dugouts, mines, and barbed wire.

Nor do most credible historians put must stock in fantastical ideas of a secret petrol-pumping system that would have lit the English Channel on fire. Such an idea didn’t work for the Israelis in 1973 in the Suez Canal, a body of water 1/100 the size, without currents or surf, and after six years of preparation. It wouldn’t have worked here.

Records of Churchill’s order to use mustard gas on German invasion troops are a little more credible, but not in the early fall of 1940. First of all, sufficient stocks of such chemical weapons wouldn’t have been available since they were destroyed by treaty after World War I. Also, civilians had not been evacuated from these coastal areas.


The simple fact is that British coastal defences in September 1940 were thin and brittle. The coastline open to possible attack was twice the length of the French and Belgian borders the Germans had just overrun, and the British now had to hold it with one-quarter the troops and one-tenth the heavy equipment.

That said, the Germans would have had the devil’s own job trying to cross the Channel in their “invasion fleet” of converted fishing boats and river barges. Even if they owned the sky, they would have taken terrible losses just getting out of the water. On both sides, this would have been “Normandy: Amateur Hour.”


Again, German tactical air power offers the only real hope such landings could have been carried off. However, the Luftwaffe would have been tasked not only with supporting the infantry, but also protecting the invasion corridor from the Royal Navy, and protecting the airborne landings.

How well could they have accomplished all three missions...at once?

The Germans had a few surprises ready for the beaches, though. Among these were the “tauchpanzers,” tanks modified to travel for a short distance underwater and crawl up onto the beaches. Four battalions (160 tanks, mostly PzKpfw-III variants) were ready for S-Day, designated battalions “A” through “D”.


In our Panzer Leader game, the Germans took predictably heavy losses trying to get ashore. Only Luftwaffe airstrikes (and off-board artillery strikes called in from huge 12” and 15” guns in Calais) were able to suppress British coastal artillery emplacements.

Once a foothold was established, however, the game was up. Outnumbered British regulars, territorial rifle units, and even Home Guards were no match for a “First Wave” German infantry division like the 17th.

Folkestone was soon outflanked and taken, opening a port for heavier German units to land on S+1, including panzer formations.

What do you think of our Sea Lion scenarios so far? The Germans may have managed a lodgement here, but this is just a small part of the invasion front, and the campaign has a long way to go.

Keep the conversation going in the comments below, and come back next week to see how far “Seelöwe” will actually go.

By James Johnson

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"...it’s now time to actually “give the go-code” and launch this hypothetical World War II invasion of southern England"

"The simple fact is that British coastal defences in September 1940 were thin and brittle..."

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