Offbeat (AKA The Devil Inside in the U.S.) is a 1961 black-and-white British crime film directed by Cliff Owen and starring William Sylvester, Mai Zetterling, and John Meillon. In the film, an MI5 officer goes undercover to catch a criminal gang.
TV Guide gave the film 2.5 out of four stars, calling it a "good programmer" ; and Mystery File wrote, "after a slow beginning, I’d have to say that halfway into the film if not earlier, I was hooked to the screen, waiting for the answer. A minor film, to be sure, but recommended, definitely so." The film historians Steve Chibnall and Brian McFarlane describe it as "a work of genuine ideological dissonance which questioned the conventional wisdom about crime and punishment", and they note that Kinematograph Weekly said at the time that Offbeat "carries a kick of one twice its size".