How was Britain defended in the World War 2?

Actually Germany declined to invade Great Britain as Hitler was much more into invading Russia (big mistake #1). Great Britain however did put a lot of effort into fortifying its coast-line, had the world's best navy and the RAF worked over-time fighting against the constant bombing. Canadian forces were stationed in England as a home guard until the D-day invasion of Europe.You could say everyone involved were defeat by ww2, economy wise, everyone lost so much money, hence the great depression.