9. The Spy In Black (1939)
The Spy in Black is the first film collaboration between Michael Powell and Emeric Pressburger, two of Britain's most influential filmmakers who would go on to make 19 more films together. In 1917, Captain Hardt (played by German expressionist film star Conrad Veidt) is ordered to attack the British fleet off the coast of Orkney. There he has to contend with, among other things, a traitorous British officer, a woman who will not reciprocate the love he feels for her, and cases of mistaken identity.
Even now, The Spy in Black proves to be an utterly compelling spy thriller, capably handled by Powell and Pressburger - a sign of things to come from their outstanding careers. For the time, the production value is outstanding, and the unpredictability of the plot lays a template for any good wartime thriller. Without giving too much away, the surprisingly empathetic portrayal of the Germans is also a bold choice given how the film was released barely months before the start of World War Two.
Powell and Pressburger went on to direct some of the most influential films in British history, such as A Matter of Life and Death (1946) and Black Narcissus (1947).