Churchill in five minutes, by Scott Johnson.

From the video:

The point about Churchill in 1940 is not that he stopped a German invasion, but that he stopped the British Government making peace. If Churchill had not been Prime Minister, the pro-appeasement foreign secretary Lord Halifax would have been. We know that Halifax was open to negotiating with Hitler. We’d be mistaken to assume that the German Fuhrer’s terms would not have been reasonable. They probably would have been very reasonable, as Hitler wanted to fight a one-front war against Russia. … Churchill made this impossible.

The concluding paragraph of The Gathering Storm, giving us Churchill’s thoughts on the evening of May 10, 1940:

During the last crowded days of the political crisis, my pulse had not quickened at any moment. I took it all as it came. But I cannot conceal from the reader of this truthful account that as I went to bed at about 3 A. M., I was conscious of a profound sense of relief. At last I had the authority to give directions over the whole scene. I felt as if I were walking with Destiny, and that all my past life had been but a preparation for this hour and for this trial. Eleven years in the political wilderness had freed me from ordinary party antagonisms. My warnings over the last six years had been so numerous, so detailed, and were now so terribly vindicated, that no one could gainsay me. I could not be reproached either for making the war or with want of preparation for it. I thought I knew a good deal about it all, and I was sure I should not fail. Therefore, although impatient for the morning, I slept soundly and had no need for cheering dreams. Facts are better than dreams.