How did the British defeat the German invasion plan in 1940?
By winning the Battle of Britain. Germany did not have a strong navy compared to Britain. They also did not have any specialised transport and landing craft for such an invasion. If they were going to get their troops across they would have to depend on already existing transport craft. In order to do that succasfully they had to have complete control of the skies over the channel in order to protect the slow and unarmed transports. Because they were unable to destroy the British air force it was impossible for them to even try to invade. Michael Montagne