I went to see Hector at Cowley Road's wonderfully intimate Ultimate Picture Palace, which preceded a fascinating Q&A with first-time director Jake Gavin (an established photographer who also wrote the screenplay), the unrelated actor Natalie Gavin, who portrayed a young homeless woman, and Lesley Dewhurst, who oversees the Oxford Homeless Pathways charity.

While the director stressed that he was keen to avoid it being a didactic 'campaign' piece, the film was about homelessness, although it primarily focussed on the life of just one man; for a large part, it concerned itself more on his condition than what lay behind it. Shot in a way that vividly portrayed his itinerant existence, it only revealed the circumstances that precipitated the subject's descent into vagrancy towards the end – which, admirably, left many questions unanswered.

For this tough, social-realist road movie (described by the director as 'Paris, Texas set on the M6'), David Raedecker's cinematography captures all these 'non-places' with a bleak, unsparing clarity, portraying hospital wards, transport cafés, service stations and motorway lay-bys as lifelines of comfort (however scant) for Hector, played by Peter Mullan. In this harsh environment, basic comforts are hard-earnt through painstaking routine, and the physical toll such a gruelling life takes is palpable.

Gina McKee, Sarah Solemani and Stephen Tompkinson provide great support, but the film is less about star turns than it is an exercise in empathy, recalling Ken Loach's My Name Is Joe in Mullan's understated and naturalistic performance. Following the protagonist in long takes, it shares Loach's documentary style and sense of compassion for those on the margin of society, while it distinguishes itself with some audacious use of music.

The discussion that followed the film was involved and rewarding, with responses to audience contributions that covered both production (budget, casting and distribution) and the societal issues that clearly underlie the film and the commitment demonstrated by all involved in the project.

Sadly, it was no surprise to learn that funding for homeless charities in Oxford is being cut, and this important film serves as a stark reminder that such unfortunate circumstances could happen to anybody. Powerful and warm-hearted, and tempered by moments of humour and kindness, it brings with it a seasonal resonance for its portrayal of Christmas celebrations in adversity.