Dir: Joanna Hogg. UK, 2007, 100mins

British film-makers have never been comfortable making thoughtful, provocative arthouse movies about the tribulations of bourgeois families. It is a style of film-making in which the French have long excelled but that UK directors generally steer clear of in case of being thought affected or pretentious. Perhaps this is why Joanna Hogg's debut feature seems so refreshing and unusual.

The film, which receives its world premiere at the London Film Festival this month, is likely to enjoy a vigourous festival life and at least some critical support. Distributors will take a lot of convincing that a story as enigmatic and oblique as this has theatrical potential, but if a UK buyer swoops, others may follow. Manwhile, foreign buyers may be intrigued by a British project that is neither a romantic comedy nor a gangster pic nor an irony-riddled farce, but has the courage to engage with ideas and emotion.

As the narrative begins, a middle-aged woman called Anna (Worth) turns up by dead of night at the Italian holiday villa of her old friend Verena (Roscoe) and her family, which includes several teenagers. To Verena's surprise, Anna's husband has not come with her. His non-appearance is the source of the mystery and tension which run through the film. We never see him, although we hear Anna speaking to him on his mobile.

Anna, it soon becomes apparent, is far keener on spending time with the teenage children than with her own contemporaries. They are flirtatious, hard-drinking and mischievous and seem to reinvigorate her after whatever trauma she has just endured. In particular, she is drawn to Oakley (Hiddleston), an arrogant and reckless figure whose relationship with his father becomes increasingly strained over the course of the holiday. The teenagers refer to their parents as 'the olds'. The attrition between generations initially seems humorous, but it soon becomes apparent that there is real dislike between them.

The film has its longueurs. At times, it verges on the self-indulgent and its protagonists - upper-middle class types on holiday in Italy - can begin to jangle on the nerves. Nonetheless, writer-director Hogg probes away at the tensions between friends, spouses and generations in an insightful and always atmospheric way.

Hogg is helped by Oliver Curtis' rich, dark cinematography and his painterly compositions. Her choice of landscape is likewise astute. The film is set in a picturesque part of rural Italy, with rolling fields, balmy skies and beautiful old buildings. (Had we been back in the UK, in the Home Counties or London suburbia, the impact would have been very much diminished.)

Hogg, who shot the film using a mix of actors and non-professionals, uses off-screen space in inventive fashion. (One of the best scenes in the film is the brutal row between father and son which is heard, not seen, as the rest of the guests sit by the swimming pool listening.) She also elicits an affecting, if slightly awkward, performance from Worth as the fortysomething woman whose life is coming off the rails. The relatively spare use of dialogue is a strength, helping add to the air of tension and mystery.

Not much happens in terms of plot, but as the great French director Eric Rohmer has shown in several of his films, sometimes showing the interplay between characters on holiday is drama enough. On vacation, Rohmer notes, people 'have time to reassess their lives.' They question their usual assumptions and will often behave in a far more anarchic and subversive way (socially and sexually) than in their normal existence. That is certainly the case here.

Disappointingly, the air of mystery that initially makes Unrelated tantalising soon begins to dissipate. The revelations which explain Anna's behaviour, when they finally arrive, are anticlimactic. The more characters reveal of themselves, the more banal they begin to appear. The film ends in a strangely lacklustre and conventional way. However, at its best, Unrelated is creepy and atmospheric and hints at the tensions which distort the lives of even the most well-adjusted families.

Production company/international sales
Raw Siena Limited (UK)
(44) 7766 663348

Producer
Barbara Stone

Screenplay
Joanna Hogg

Cinematography
Oliver Curtis

Production design
Stephane Collonge

Editor
Helle le Fevre

Main cast
Kathryn Worth
Tom Hiddleston
Mary Roscoe
David Rintoul
Henry Lloyd-Hughes
Emma Hiddleston
Michael Hadley
Harry Kershaw