The shot of the wooden building being blown up towards the end was from one of the British Commando raids on the Norwegian coast. These were usually to attack things like fish-oil processing plants. Various other extracts from newsreels or other reality footage were inserted into this film at various points.
Arthur Greenwood was a Labour member of the British House of Commons from 1922 to 1931 and from 1932 to 1945. He was Deputy Labour leader from 1935 to 1945. He served in Sir Winston Churchill's wartime cabinet from 1940 to 1942.
Metcalfe's quote, "Night's candles are burned out and jocund day stands tiptoe on the misty mountain tops ...", is from 'Romeo and Juliet', Act III, Scene 5 by William Shakespeare.
Extras for the assault scenes on the Norwegian coast included both Norwegians who had only recently escaped to England - many wearing their real kit - and British "Tommies", some of whom had made the same assault landings being recreated in this film.