When this movie was made, America was not part of World War II. At this time, a number of Hollywood studios were pro-American involvement in the war. This movie is one of a number of films made during the late 1930s and early 1940s that represented pro-American intervention in the war. These films include: A Yank in the R.A.F., Man Hunt, Foreign Correspondent, The Mortal Storm, Confessions of a Nazi Spy and Sergeant York.
When Thorndike (Pidgeon) is captured, the George Sanders character inspects his belongings including his rifle, which bears the maker's name of "Hammond and Hammond, Bond Street". There was no such gunsmith in the UK and it seems likely the name is borrowed from a very famous gunsmith called Holland and Holland of Bruton Street, which is situated nearby.