What was unusual about the Battle of Britain?

The Battle of Britain (10 July–31 October 1940) is the name given to the defence of the UK by the RAF against an onslaught by the Luftwaffe. The three statements are explained as follows:

(1) In a speech on 18 June Winston Churchill said "... What General Weygand has called The Battle of France is over. The battle of Britain is about to begin... The whole fury and might of the enemy must very soon be turned on us. Hitler knows that he will have to break us in this island or lose the war. If we can stand up to him, all Europe may be free and the life of the world may move forward into broad, sunlit uplands. But if we fail, then the whole world, including the United States,... will sink into the abyss of a new Dark Age."

(2) An important factor in maintaining public morale was the continued presence in London of King George VI and his wife Queen Elizabeth. On 24 September, in recognition of the bravery of civilians, the King inaugurated the award of the George Cross.

(3) Because of Britain's geography, an assault could only come from the sea or the air and a seaborne assault would require air superiority. Air attacks had to come across the English Channel or, more perilously, across the North Sea.