Churchill rallied the British people with his rhetoric and his resolve.  As John Kennedy aptly put it, he "mobolized the English language and sent it into battle."  Here is an excerpt of his inspiring speeches, which steeled the British people to win the Battle of Britain.  Or, if you have Real Audio loaded on your Multimedia computer, you can hear Churchill speak to the British people over radio, rallying them to victory on the eve of the Battle of Britain, simply by clicking here

"This was their finest hour."
                                June 18, 1940

Churchill delivered this speech to the House of Commons, and then broadcast it over the BBC to reassure the nation, the Commonwealth and the United States that the fate of France would not befall Britain. In this historic speech he uttered the immortal words, "Let us therefore brace ourselves to our duties, and so bear ourselves that, if the British Empire and Commonwealth last for a thousand years, men will still say, "This was their finest hour."
 
 

What General Weygand called the Battle of France is over. I expect that the Battle of Britain is about to begin. Upon this battle depends the survival of Christian civilization. Upon it depends our own British life, and the long continuity of our institutions and our Empire. 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, including all that we have known and cared for, will sink into the abyss of a new Dark Age made more sinister, and perhaps more protracted, by the light of perverted science. Let us therefore brace ourselves to our duties, and so bear ourselves that, if the British Empire and its Commonwealth last for a thousand years, men will still say, "This was their finest hour."

    Churchill also impressed Franklin D. Roosevelt and successfully persuaded Roosevelt to support the massive infusion of aid to Britain in the form of Lend-Lease provisions.  Roosevelt persuaded American public opinion by skillfully mixing isolationist arguments, idealistic arguments, and appeals to national and geopolitical self-interest.  The success of the Lend-Lease Bill (in May 1941) was assured when Roosevelt defended it in the most widely-heard radio address of his Presidency, his "Four Freedoms" speech, and in his State of the Union speech of January 1941, excerpts of which you can hear as it was delivered (if you can process WAV files), merely by clicking here.

The second secret weapon was the joint American and British development of radar, which the British used effectively in the Battle to counter German numerical superiority.  Disgusted with the failure to defeat Britain quickly, Hitler made the first of his three big mistakes of the war, diverting the Geman bombers from the British air fields, which were in alomst catastrophic shape, to the civilian centers in a vain attempt to break civilian morale.  Strategic bombing, which both sides never ceased believing would work, was tried by both sides with equal failure on both sides (until the cause was hopeless). The air fields were repaired and the Royal Air Force took to the skies to achive an air supremacy they would never again relinquish.