We've had docudramas, mockumentaries and dramedies. But we need a new hybrid term to describe The Arbor, Clio Barnard's film about the fierce, abbreviated life of the Bradford playwright Andrea Dunbar, who knocked out three plays and three nippers before collapsing in her local and dying of a brain haemorrhage at the age of 29. The Arbor throws documentary interviews, reconstructions, Brechtian flourishes and the conventions of verbatim theatre into a giant washing-up basin; it's kitchen-sink drama on a sink estate. But what on earth should we call it? Apart from good and grim and covered in scar tissue, that is. Answers on a packet of ten Silk Cut.
Dunbar's first play, written when she was 15 and produced five years later in 1980, was a profane slab of uncooked autobiography called The Arbor, named after Brafferton Arbor on the Buttershaw housing estate where she grew up, and where she was still living at the time of her death. The play touched on teenage pregnancy, abortion, racism and the abusive behaviour of an alcoholic parent - all of it experienced first-hand by Dunbar. Like its naughty follow-up Rita, Sue and Bob Too, The Arbor was staged at the Royal Court Theatre in London, and Barnard has turned up revealing correspondence that Dunbar sent to her director, Max Stafford-Clark. Not "Please change 'bugger' to 'bastard' in scene 12", but the messy business of the domestic life that both informed her work and, increasingly, stood in the way of it. You can practically smell the nappies boiling in an old pan.
As well as drawing on archive footage of Dunbar from 1980s television, Barnard has interviewed some of the people who were close enough to the playwright to be singed by the sparks coming off her. Man hands on misery to man, but female playwrights can do the job equally well, as the chief witness for the prosecution - Dunbar's eldest child, Lorraine, now 31 - can testify. "One of the reasons I hated her," Lorraine says, "was I couldn't tell her as a child how I felt."
Lorraine's father was Pakistani, which Dunbar cited as the reason she loved her less. Barnard sets this cruelty in context; an excerpt from The Arbor shows the main character, based on Dunbar, being taunted as a "Paki lover" by the local riff-raff. And the film extends a small but poignant compensatory gift to Lorraine by placing her at the centre of its only euphoric image: a reconstructed shot of her as a young girl in a sari, boogieing to bhangra music on the roof of her father's Cortina, with the cramped streets of Bradford spread out below.
Gradually it becomes clear that The Arbor is not really Dunbar's story at all - it belongs to Lorraine, and restores to her the voice she was denied in her childhood. Only the voice, mind. None of Barnard's interviewees, whether it's Lorraine, her foster parents, or even Stafford-Clark, makes it on to the screen. Instead, actors lip-sync to recordings of them. The effect is unnerving, because anything in which people serve as conduits for disembodied voices is bound to have something of the seance about it.
But once the creepiness subsides, the device places vital distance between the subjects and their words - it becomes like a screen preserving the anonymity of vulnerable witnesses in court. Were it Lorraine herself reeling off her inventory of abuse and trauma before the camera, the picture would risk the overkill of a misery memoir or a Mommie Dearest. Hysteria is kept at bay by the presence of actors, including Manjinder Virk as Lorraine, Jimi Mistry as Yousaf (a character from The Arbor based on Lorraine's father) and George Costigan ("Bob" from Alan Clarke's 1986 film of Rita, Sue and Bob Too) as Dunbar's violent lover Jimmy "the Wig", shown here nursing a kitten like a Bradford Blofeld.
The film's layered structure enriches the material as well as cooling it down. Only the scenes from The Arbor itself, performed around sofas and free-standing door frames right there on the green on the Buttershaw Estate, fall a little flat; they feel too honed amid the raw material that inspired them.
But they are important, at least, for dragging the film out on to the streets. Without these al fresco interludes, Barnard's picture would be like a stretch in solitary confinement. It begins, after all, with Lorraine and her sister Lisa trapped in a blazing room after their mother goes out, taking the door handle with her to ensure their confinement. Lorraine ends the film in another enclosed space that locks only from the outside.
And yet, it has to be said that prison resembles a weird kind of liberty compared to life with Andrea Dunbar.