Could Sealion have worked if the German Panzers had not been halted and the British army was captured in full at Dunkirk?
In wargames conducted at the Royal Military Academy Sandhurst in 1974, which assumed the Luftwaffe had not yet won air supremacy, the Germans were able to establish a beachhead in England by using a minefield screen in the English Channel to protect the initial assault. However, the German ground forces were delayed at the "Stop Lines" (e.g., the GHQ Line), a layered series of defensive positions that had been built, each a combination of British Home Guard troops and physical barriers. At the same time, the regular troops of the British Army were forming up. After only a few days, the Royal Navy was able to reach the Channel from Scapa Flow, cutting off supplies and blocking further reinforcement. Isolated and facing regular troops with armour and artillery, the invasion force was made to surrender.
While I doubt Sealion could ever work, I always have issue with the "war games" proving it was doomed to failure. The war games always have the German units surrendering instantly, no major skirmish, no hold outs, just British troops find the Germans and they win.
At the time if Sealion was attempted I am positive it could take weeks, even months before people realized the operation was a failure. I mean say what one wants but Germans had damn fine soldiers. I am always of the opinion that in some manner sealion would work not as a military victory, but a paniced victory. Much like how France reacted to their swift defeat, and the Germans mobility, I could see the UK over reacting in some way to enemy troops on British soil.
Dude, if you're going to cut and paste from Wikipedia, forum etiquette dictates that you say that is what you're doing.