Perfection is not just about control. It is also about letting go – or so says Vincent Cassel as the cocksure ballet director in Black Swan. It is the destruction wrought by this pursuit of the visceral that Darren Aranofsky (Requiem For a Dream; The Wrestler) is concerned with in his new film.

But the essence of Black Swan is not so much the morality of its subject matter as its sheer intensity. The result of this is a relentless ‘psycho-melodrama’. Natalie Portman plays Nina Sayers, a fragile yet determined ballerina whose desperate desire to perfect the role of Odile the Black Swan in Swan Lake culminates in a cocktail of drugs, sex, hallucinations and homicide. But we cannot be sure of any of this, since Aranofsky does not clarify what is actually happening and what is instead the product of Nina’s growing schizophrenia, or indeed what is further still the artistic licence of a story based on a fairy tale.

The mantra of being ‘in the moment’ is reflected in each of the film’s draining yet gripping scenes. All of the main characters are dancers, from the fading star whom Nina replaces, Beth Macintyre, to Lily, the sexually confident rival, and even Nina’s own controlling mother is a dancer. The depiction of a New York ballet school evokes a real sense of the relative values imbued in a closed working community, analogous in some ways, perhaps, to Cambridge.

But Black Swan is, upon reflection, a film whose brilliant opening and closing scenes frame a number of hackneyed moments. Nina’s various visions are fairly underwhelming for the most part, and a particular instance where her mother’s paintings come to life feels disappointingly like a horror pastiche. The dialogue is suitably simple, though it might have proved lacking were it not for the conviction of each of the film’s main actors. With his invulnerable self assuredness, Cassel brings believability to a potential caricature of a French choreographer obsessed with telling his dancers to "feel it".

Where Black Swan really soars, however, is in Natalie Portman’s unceasingly compelling portrayal of Nina. Fraught with insecurity, repressed by her mother, and yearning for perfection, the dancer’s transformation from the virginal White Swan into the blood-eyed, lustful Black Swan is what the film is all about. Black Swan is visually stunning, and although its less inventive moments detract somewhat from the exquisiteness which it assumes, its highest points are utterly transfixing.