This point actually does come across in the movie as well. At least I thought it did along with the companion who saw it with me. In fact, it was stated in conversation after the movie that he had not realized just how ‘hated Churchill’ really was at the time. That peace negotiation through Halifax and Mussolini, if Churchill would have not considered it, would have led to a vote of no confidence from his own party.
With so many against him, one has to wonder just exactly who influenced him into having the courage of making the decision he made. Was it the conversation he had with King George as depicted in the movie where he makes it clear Churchill has his complete support, was it his wife, or his secretary. As pointed out several times the underground railway scene is fiction, “But then there are scenes in the movie, like the Underground scene for instance, which is a fictionalization of an “emotional truth,” as you put it. Churchill was known to go AWOL at times, no one could find him. They didn’t know where he went. And he was also known to go and visit the people of London and seek their counsel, and have a little cry with them sometimes.”
Did That Pivotal Darkest Hour Scene Really Happen? Joe Wright Fills Us In
https://www.cinemablend.com/news/1731500/did-that-pivotal-darkest-hour-scene-really-happen-joe-wright-fills-us-in
In the companion book the author makes fairly clear that in his research he could see how totally opposite Churchill and Halifax were in their approach to policy. That being said. Halifax was convinced that there was, and had to be, a true possibility for peace, while Churchill was temperamentally convinced that Hitler would not allow it. VDH, in his new book, gives us the quote that Hitler would be happy with ten years of war to get the conquests he felt his people deserved.
Halifax did not want Britain to surrender its independence in any peace negotiation and Churchill was convinced that once started, peach negotiations with a rampaging and successful Hitler would have no other outcome.