A view from a fish tank

There's an easily identifiable strand in British cinema, famously represented by Mike Leigh and Ken Loach, that probles deeply into the social fabric of UK society to expose areas that rarely make it to promotional leaflets. In fact, this fond interest in gritty, unkempt realism has its roots outside cinemas, in such quintessentially British trends as angry young men or kitchen sink drama, and finds keen continuation in assorted cultural production, for example the TV series The Royale Family.

Fish Tank, a recent gem from the award-winning Andrea Arnold, inevitably falls into this category, but - importantly - manages to extend its limits. It centres on the adolescent Mia (played by a first-timer Katie Jarvis) who marches angrily through a tense period in her teenage life, making enemies every step she takes. Confrontational and uncompromising, Mia shuttles between regular clashes with her dysfunctional mother, her indifference towards her overactive and foul-mouthed sister or drinking bouts and displays of her dedication to dancing (which she practices madly in an abandoned flat which looks like a fish tank) and her tenderness at heart (when she runs immense risks just to set a horse free). She's torn and there's nobody who can push her in the right direction or just give some respite from feeling terribly lost. Until one morning she stumbles upon Connor, her mum's new lover (a great role by Michael Fassbender, who's recently showed his extreme skill in Hunger and Inglorious Basterds). Their relationship starts out as a father-daughter thing, with Mia achingly craving a male role model and a protector, but it slowly, and tragically, degenerates into illicit romance that culminates in a drunken sexual encounter.

I sympahize with those who couldn't be bothered by the film's closing sequence when Mia chases Connor's daughter. It felt redundant and prolonged Fish Tank to the limits of my endurance. These's been some outsize sentimentalism and symbolism, too, but it's accounted for, in my view, as an attempt to breath some fresh air into staid social realism and expand its boundaries.

With no happy end, but a lot of hope in the air, Mia decides to leave her birthpace and seek better fortune in Cardiff together with her shy boyfriend (the horse-owner). The way she and her sister say goodbye, lovingly sputtering "I hate you", "I hate you, too", in the final scene is a great metaphor for how oddly confused, on the surface, life can get for the disadvantaged, while retaining depth and clarity below this surface. Another scene with the same gravity is when Mia and her mum silently part with each other in an improvised dancing routine, performed in disarming sync.