In this World War II drama based on true events, a group of British POWs suspects that there is a German spy in its midst after several escape attempts are foiled. Deftly directed by Lewis Gilbert (“You Only Live Twice”, “The Spy Who Loved Me”) and supported by Jack Asher’s moody cinematography, “Albert R.N.” stands beside “Stalag 17” and “The Great Escape” in the World War II/POW drama genre.