While the invasion never actually took place, Great Britain did take a number of steps to prepare for it. These steps included:
* Building up the Royal Air Force (RAF): The RAF was greatly expanded in the years leading up to World War II, and by 1940 it was one of the strongest air forces in the world. The RAF played a crucial role in the defense of Britain during the Battle of Britain, and its victory over the Luftwaffe was a major factor in the failure of Operation Sea Lion.
* Constructing coastal fortifications: The British built a number of coastal fortifications, including gun batteries, pillboxes, and anti-tank obstacles, to deter a German invasion. These fortifications were concentrated along the southern and eastern coasts of England, which were considered to be the most likely landing sites for the Germans.
* Establishing the Home Guard: The Home Guard was a volunteer civilian force that was created in 1940 to help defend the country in the event of an invasion. The Home Guard was armed with a variety of weapons, including rifles, shotguns, and Molotov cocktails, and was trained to fight guerrilla warfare.
* Evacuating civilians from coastal areas: In the weeks leading up to the expected invasion, the British government evacuated hundreds of thousands of civilians from coastal areas to safer areas inland. This was done to reduce the number of casualties in the event of an invasion, and to make it more difficult for the Germans to find and capture the British population.
These steps helped to prepare Britain for the German invasion, but ultimately it was the failure of the Luftwaffe to gain air superiority that led to the cancellation of Operation Sea Lion. The RAF's victory in the Battle of Britain showed that the British were determined to fight and that they had the means to do so, which convinced the Germans that an invasion would be too risky.