The complex motives of the abuser are put under the spotlight in this bleak drama of nihilism and despair on an inner-city housing estate
Gary's Oldman's first film as writer and director is a fierce and fatalistic family drama set on a housing estate in south-east London. If the script was written by an outsider, it would seem like a class libel, but since Oldman can claim this milieu as his own, it's at least a libel with some authority.

The men express themselves in boastful comic monologues about sex and criminality, some of them reminiscent of a less characterful Stephen Berkoff, falling briefly silent by wary reflex when they hear the siren of an emergency vehicle. The women stay quiet in the background, hoping to miss out on the next round of insults and abuses.

Ray (Ray Winstone) dips into the drugs he sells, and is amply distorted by them, though he's in a less obviously desperate state than his kid brother-in-law Billy (Charlie Creed-Miles), addicted to heroin. The only time that Billy looks anything other than gormless is when he is cooking and administering a fix - he's almost ennobled by concentration on the task. Even in a police cell he manages to feed his habit.

Ray's wife Valerie (Kathy Burke) has a five-year-old girl, and is expecting another baby. Her mother and grandmother are near-neighbours; a certain amount of caring and support comes from the female side of the family. It is the women who supply the few wistful signs of culture in the flat, a group of ceramic Siamese cats here, a reproduction Modigliani there.

This is anything but a matriarchy, though. Valerie's mother (Laila Morse), the only character with a legitimate job, has no influence over her son- in-law's aggressive behaviour, and even her Granny Kath (Edna Dore) will do as a target for Ray if there's no one else around. In one scene he asks her for a hug, then insults her sexually. After she leaves, he assures the empty room, in between swigs of vodka, that all he was doing was having a giggle, then goes out with a bizarre parting shout of "Love You! All right?"

These lives are bleak in part because of the place where they are lived. Nil By Mouth was filmed on the Bonami Estate in Deptford, since demolished. Oldman's director of photography, Ron Fortunato, gives the exteriors an occasional perverse duty, filmed in morning mist with fluttering pigeons, without ever making the estate look fit for human habitation. A local kid, playing grimly in the recreational space provided, gives strangers a baleful look that is wholly understandable.

The film is not primarily making a political or social statement, however. The character of Ray is a cause of suffering to those around him, a viscous mystery inexplicable in terms of environment. In the scene which will come to represent Nil By Mouth in the minds of those who see it, he wakes Valerie to accuse her of evidently non-existent infidelities and beats her savagely with fist and foot.

This is not a particularly explicit scene by contemporary standards (we don't see blows landing). Oldman delays the full impact until we see the extent of Valerie's injuries, the swollen bruising and closed eye. Threatened by Ray that worse will happen if she goes to hospital or blames him, she tells her mother she was knocked down by a car - a hideously credible explanation of her condition. Only after she has lost her baby does she tell the truth.

It would be unfair to say that the film makes excuses for Ray, but it is at this point that Oldman chooses to explore the character's interior. He does this in two set-piece scenes, rhetorically heightened in the film and writing. First, Ray begins to come apart into separate shards of rage, self-pity and denial, talking to Valerie on a phone he has ripped from the wall. Sound and image are deliberately fragmented to produce a stylised montage of masculinity imploding. Then Ray expresses to his incomprehensibly loyal mate Mark his own feelings of being rejected by his father, in terms that have sudden lurches into the literary: "He weren't like other kids' dads. It was as if the word itself was enough for him..."

The psychology of the abuser takes precedent over that of his victim. We never know why Valerie chose Ray, or stayed with him, except for being told that she wanted another child, and didn't want a different father for the newcomer. The men's language in is fractured cliche (Billy's all purpose "Blinding!", Mark's equally versatile "Sweet as"), hers is untransformed - "I'm sick of the pair of you", "You'll need that getting looked at".

Valerie's mother says: "We are unlucky, aren't we?" then "Do you still love him?". She doesn't answer, but after a few weeks of numb defiance, she takes Ray back. Nil By Mouth would be more impressive if it didn't hurry over this crucial failure of nerve - Valerie's decision obliquely conveyed to us by her Gran singing: "Can't Help Loving That Man of Mine" in the pub. Even in this supremely dysfunctional family, after all, we have seen glimpses of Agnus, a Scottish in-law who seems undistorted by the addicted damage around him. But Gary Oldman's film earns the great, if back-handed, compliment of being powerful enough to argue with.

`Nil by Mouth' goes on release today