He was resolutely ignored by Chamberlain who intensely disliked Churchill. Even after Hitler attacked Poland, Chamberlain naively thought he could make a deal with Hitler. He only realized his foolishness shortly before he gave up party leadership and the P.M. to Churchill.
After the May 1940 debacle when Hitler's armies crushed the Allied forces in France, Hitler was sure England was finished. After France gave in he was absolutely sure Britain would sue for peace. He didn't know Churchill. Churchill would rather have died with a smoking pistol in his hand rather than surrender. And Churchill did carry a revolver around.
Shortly before he committed suicide Hitler told one of his flunkies that while he still liked the English people in general, Churchill was the only one didn't like.
The Leader's last words in the book: "I am Prime Minister Winston".