Was a German invasion of southeastern England even possible in 1940?

[deleted]

No, it wasn't possible. Not in 1940. Fact is when France surrendered there was absolutely no plan, not even a consideration in fact, about launching a naval invasion of Great Britain. Hitler believed the UK would never continue the war. When it became apparent that a naval invasion might be necessary they had to scramble a plan relying on outdated information and no realistic way of carrying it out. It was a recipe for disaster.

Here's something to consider: The English channel and its treacherous waters has prevent many an invasion over the centuries. William the Conqueror had a lot of luck and a minor delay would have sunk his entire invasion fleet. Any invasion fleet would never consider launching after a certain date in September, when the waves become too high and the German landing ships would be defeated by the forces of nature long before they ever made it ashore. So Nazi Germany only had a few months to: 1. Decisively defeat RAF. 2. Find enough transport ships to even make a landing possible. 3. Hope everything goes to plan when they hadn't trained for this and never had attempted such a campaign before.

The Kriegsmarine wasn't ready for war when it broke out in 1939 and it could never challenge the Royal Navy on even terms in 1940. At this time the Royal Navy was the largest navy in the world, and the Americans only overtook its size in 1944.
Even IF the RAF had been knocked out Nazi Germany simple didn't have enough landing ships with which to land enough troops and equipment. They planned on using river barges from all over occupied Europe. Needless to say these bargest weren't anywhere near as seaworthy as the landing ships the allies used to invade Normandie in 1944. Most of these barges didn't even have their own propulsion and were supposed to be towed by other ships. Those who did have their own propulsion were so slow it would have taken 14 hours to cross from one shore to another - all while the Royal Navy attacks them with any war ship that floats. They wouldn't even have to shoot at them just drive past them and they'd founder and sink.

It was estimated by the Germany navy that they could land 9 divisions at most. It was also estimated that they needed three times as many divisions landed to make the invasion successful. The Kriegsmarine did NOT have the naval capacity to pull Operation Sea Lion off in 1940 - even if the RAF had somehow been knocked out.

Lots of transport aircraft were lost in the invasion of the Netherlands in 1940 and it was also doubtful Germany could land enough paratroopers.

The allies planned for Operation Overlord for over a year, had trained troops that had trained for months before and who had expertise with naval invasions (Operation Torch for instance in North Africa).

Once the Royal Navy gets to the beaches the invasion is over. Even if the Luftwaffe sinks a few of them they'd take a lot of Germans with them and their share numbers will win the day.

Had Operation Sea Lion been attempted in 1940, with no well-thought out plan or accurate information, without trained troops, without enough landing ships (slow river barges remember) and without enough ships to supply whatever small force they could land it would have ended in disaster with our without the RAF being there.

Time wasn't on the side of the Germans.

I've discussed this enough to have come to the conclusion that the invasion of Britain was almost impossible.

There was a very VERY small chance that it would have been successful, but not enough to warrant the gamble.

Having said that, that conclusion comes AFTER the event. There were powerful, well learned US officials IN BRITAIN that thought invasion was a forgone conclusion and that Britain was doomed... and there were probably many extremely worried Brits as well, but post WWII history shows that the Germans just didn't have the experience or the equipment to land a sizable force in Britain.

Sure, British equipment was lacking, but it wasn't like the entire British army was left in Dunkirk.

So, my conclusion goes like this:

IF the Germans got decent air superiority over South Eastern England then there would have been a serious attempt at invasion, which would have dramatic ramifications on WWII. The Germans would have lost a LOT of valuable manpower in said invasion attempt. Some troops would have gotten ashore, but the RN would have made merry hell out of the invasion flotilla. That of course would have meant lots of His Majesty's Ship at the bottom of the English Channel, but it would have also stopped any decent invasion. Consider how Overlord went with overwhelming air superiority, and TOTAL control of the English Channel, and a not insignificant amount of experience in doing invasions from the sea.

So, we have a weakened German Army, which may inspire a more active Soviet threat. The RN would be dramatically reduced and a very VERY different 1942.


SpiltPersonality

All it would have taken is to have an decent airbase in southeast England and the Germans could have poured men and equipment into England. The British army left their weapons and heavy guns at Dunkirk and they had not been replaced. The immediate objective would have been "to march down Whitehall" and impose surrender terms. Total defeat was not required. Hitler saw Britain as a "natural Ally". He wanted British soldiers on the Russian Front.