So said General Smuts on July 21, broadcasting to Britain, and the United States. "Nothing that has happened so far in the war justifies the inference that the fate of Britain will follow that of the other countries that have been overrun. The correct inference is just the opposite. How different, indeed, how unique, the case of Britain is, is forcibly illustrated by the most astounding incident of the whole war.
I refer to the escape of the British Expeditionary Force at Dunkirk. If ever a force was trapped and doomed, it was the B.E.F. at Dunkirk. The German Government announced that it was trapped, and their High Command concentrated the bulk of their vast bombing force in an effort to achieve this crowning victory ... If the German Army and Air Force together could not succeed in their attack at a single point like Dunkirk, how can they fairly hope to succeed in an attack on such a huge area as Britain, where, moreover, every physical and moral factor would be vastly in favour of the defence? ... If Dunkirk has any message for us it is the heartening one that Britain will prove an impregnable fortress against which Germany's might will be launched in vain. If that attack fails, Hitler is lost and all Europe, aye, the whole world, is saved."

July 1940