One of the reasons Britain stood firm is that it had technological superiority over Germany. It's aircraft were superior both in design and construction. It also developed superior radar and employed computers to break the Enigma code system. The atomic weapon was essentially a British technology moved to America where it could be more safely developed.
Germany's main advantage was in submarines and tanks. But even their tanks were not as advanced as is commonly believed. They were highly successful early in the war due to numerical rather than technical advantage.
Even the much lauded "Stuka" was a only a limited light bomber rather than the aerial superiority fighter often portrayed in movies.British technology gave birth to the mighty Lancaster heavy bomber that decimated Germany with carpet bombing raids.
British technology also enabled them to destroy German dams as the famous Dam Buster squadron proved.