It’s 1978 and General Pinochet’s military dictatorship has a tight grip on Chile and its citizens. In the midst of this, fifty-something Raul and an amateur group of dancers perform dance routines from Saturday Night Fever at a small bar on the outskirts of Santiago. But for Raul, imitating Tony Manero, John Travolta’s character in the movie, is not just a chance to perform – it’s an obsession. He really wants to be Tony Manero, and his desire to imitate his idol drives him to commit murder and to betray the only people who ever loved him.

Chilean director Pablo Larrain’s second feature is not only a brutal and disturbing psychological thriller, it’s also a shocking social commentary on the Chilean psyche. Social outcast Raul lacks his own identity as he reaches out through the movies to embrace a world outside his own. So too does Chile lack any real identity, as it suffocates under Pinochet’s reign of terror.

Raul is a deeply unpleasant character. He has a callous unconcern for the feelings of others, disregards social norms and is incapable of love. But bring into context a world filled with paranoia, fear and corruption, and Raul becomes less a monster and more a victim of his surroundings.

Even his acts of violence have a perverse logic. He kills an elderly woman living in a nice apartment provided to army widows for her colour TV, steals a watch from a dying man who was shot by the secret police, and kills a scrap-yard merchant after he cheats Raul on a sale.

When Raul gets the chance to impersonate his hero on national TV, there’s a sense that winning the contest will somehow justify his immoral deeds. But his obsession is eating him alive – highlighted by his childish attempts to stop his best friend from appearing on the show with him by soiling his suit.

Shot with gritty realism, Tony Manero, is no homage to the 1970s, and definitely no walk in the park. But like Travis Bickle, the anti-hero of 1976’s Taxi Driver, who became fed up with the moral decay infecting American society after Vietnam, Tony Manero’s low-life obsessive Raul is also saying something very significant about a country that lost its soul.

Released 28 September on DVD and Blu-ray