4. Scum (1979)
Alan Clarke's 1979 drama - adapted from a shorter 1977 version - is unquestionably rough around the edges, but that only accentuates both its charm and impact, in what was one of the first cinematic indictments of the British rehabilitative system. Winstone plays the protagonist, Carlin, a young offender who arrives at a Borstal, and slowly but surely works his way to the top through extreme violence and manipulation. Hugely controversial but completely essential, by association the film managed to raise a young Winstone's profile early in his career, and helped him gain more notoriety as a "tough man" type. After all, who can forget the iconic moment in which Carlin places two snooker balls inside a sock, and then proceeds to beat several men with it? It goes without saying that Winstone managing to convey so much menace despite his relatively fresh face and slighter frame is no mean feat; it's proof of his inimitable screen presence, and thus it's no surprise he went on to become such a statuesque figure in this sort of film.