All this really needed was someone like Emil Jannings to add a bit of imperialist, silent-film, gravitas to proceedings as a pair of slightly self-obsessed intellectual ne’er-do-wells get caught up in the Franco-Russian war. Unfortunately for the Czar, with Napoleon clamouring at his borders, he must rely on the likes of the neurotic and yellow-bellied “Boris” (has to be Woody Allen, doesn’t it?) to enlist in his…