Screenwriter Anthony McCarten made tweaks to his Darkest Hour script after receiving suggestions from actors Gary Oldman and Kristin Scott Thomas.

The Oscar-nominated screenwriter penned the screenplay for the Winston Churchill biopic, which follows the British Prime Minister as he decides whether to negotiate with Adolf Hitler in the early days of World War II.

Once actors have been cast in the roles, Anthony generally gives the script some tweaks to fit them, and one day on set, Gary, who plays Churchill, asked if he could be given a moment to shout. Following his request, McCarten wrote it in to the script.

"I’d say to Gary, ‘What do you think he should shout about?’ and he’d say, ‘I have no idea, but I had a very quiet scene before this and I think it would be very effective if I shouted,'" McCarten recalled during a Q&A at BAFTA in London.

"When he does his first radio broadcast I decided to have him changing the speech up to the last second and he shouts at the BBC guy who’s counting in and saying, ‘Sir we’re going live to the nation, three, four, two, one,’ and he’s shouting, ‘One moment, damn you!’ and that’s Gary wanting his shouting moment and it’s very effective."

His collaboration with Kristin was far more substantial as she pushed for her portrayal of Churchill's wife Clementine to have more screen time.

"It became apparent that she thought her role was kind of one scene too few," Anthony explained. "And she had damn good reason for thinking that. It fell upon me to write another little scene for her, but it wasn’t just something for her vanity or anything, it was ‘we can go further with that character.'"

Before the actors even got involved, the writer, who was nominated for the Best Adapted Screenplay Oscar for The Theory of Everything, also made a new draft after having discussions with the director Joe Wright about making the storytelling more cinematic.

McCarten doesn't mind making these little adjustments, likening his job to making a suit which then needs to be tailored to fit the person.