This unusual but typically low-key product from Ealing Studios (best-known for a series of classic comedies made between 1946-1955) is a semi-documentary depiction of the saboteur training undergone by a band of hand-picked civilians and their subsequent missions behind enemy lines; therefore, in both theme and quality, it anticipates the later, more acclaimed Hollywood offering DECISION BEFORE DAWN (1951) which, incidentally, I just caught up with a couple of weeks ago. The cast is mostly made up of the usual familiar British faces (James Robertson Justice, Gordon Jackson, Jack Warner, Robert Beatty, etc.) but 2 major roles are, very effectively, portrayed respectively by French and Canadian actors: Simone Signoret (appearing in her first English-speaking film when on the verge of attaining stardom on her home ground) and Paul Dupuis. Being in this company, there cannot fail to be lighter moments especially during an early sequence where our heroes are being shown the tools of their trade i.e. booby-trapped dead rats, manure and even sausages! among the continuous perils and occasional tragedies they have to face away from home (including being forced to cold-bloodedly execute a compromised companion and swallow the omnipresent suicide pill to escape torture at the enemy's hands).