In the opening scene, Churchill is shown surrounded by files, one of which is stamped BIGOT. BIGOT was an acronym for British Invasion of German Occupied Territory and was used to denote persons who had access to classified materials about Operation Overlord.
Brian Cox claimed that the cigar he smokes in the film was electric, due to Scotland's strict anti-smoking policies even for films.
Olivier Award winning lead actor Brian Cox learned the entire script as a single piece, rather than memorizing scene by scene.
One of two films being released in 2017 centered around Winston Churchill. The other being Darkest Hour (2017), with Gary Oldman.