LAST year Pat Barker of Durham in northern England came out of nowhere with Union Street, a sensational first novel in more ways than one. Now, with Blow Your House Down, Barker gives notice that she is capable of building on that early promise, although her gift is emerging as one of intensity rather than range.

Like Union Street, this book drops us down into a world as remote from the civilized habitats of most modern novel- readers as the dark side of the moon. Set once again in a northern industrial English city, it is a fictional re-creation of the lives of a circle of prostitutes -- Brenda, Audrey, Elaine, Jean, Carol, Maureen, Kath -- during the period in the late 1970s when the psychopathic killer known as the Yorkshire Ripper terrorized women from Leeds to Manchester. If Pat Barker's trademark is to be a preoccupation with the sordid, miserable and violent aspects of human life, then this is obviously an inspired choice of subject.

The women close ranks, even though individually isolated by fear, as the killer picks off first one, then another, and another of their number. A rough, but fiercely loyal, sisterhood is formed. The women are not for an instant sentimentalized; theirs is a tough and ugly business and, as Brenda puts it, "a skin had formed over her mind" in order to survive in it. "Everything seemed to be happening on the other side of a dirty glass." But with their little kids, their drinking problems, their pride, their superstitions, their slangy wit, they grow as real to us as neighbors. Their deaths are shocking because their lives are given full value.

Barker's great achievement in Blow Your House Down is in the way she creates, with a minimum of descriptive writing, the desolate world of the prostitutes and at the same time lets that world reflect particular states of mind. There is a landscape, a mood, of the modern inner city which she is beginning to make her own: night, cold, rain, wind, boarded- up streets, cruising cars, empty row-houses, "the sodium orange of the street lamps" and, above all, the killer's hunting-ground, "down . . . where the arches of the great railway viaduct soared overhead and trains rattled and flashed across the sky," where Kath's voice "lost itself among the dark vaults and dripping walls." Grimness as unrelenting as this harks back to 19th-century images of the industrial city, to Blake, or Disraeli, or Engels on the slums of Manchester in 1844. Certainly, the sense of moral outrage which pervades Pat Barker's writing is in just such a tradition of social indictment.

The dramatic highlight of the book is the murder, from the point of view o the Ripper, of the aging prostitute, Kath Robson. To describe this episode as obscene is not, in the context of the book's almost missionary passion for revelation, enough. Barker seems deliberately to use the language of obscenity because obscenity itself -- that which incites to depravity, thus evil in the broadest sense -- is what's at issue. Of course, this may not be reason enough for anyone to want to read about it. It should be said that Barker's attempt at obscenity-as-technique is restricted to this single episode. However, it does reverberate horrifically through the rest of the novel, and Kath Robson's dead face, plastered up on billboards all over the city, becomes one of the two main symbols for the whole.

The other, less subtly handled, is the recurrent image of the chicken factory, directly across from the viaduct, where the prostitute Brenda used to work. "A line of headless chickens, naked, with plump thighs, jerked around the room above the women's heads. At intervals they were taken down to be gutted, cleaned, chilled. trussed and frozen." Soon, chicken and prostitute merge into a single image, that of victim, which can be used to chilling, if predictable, effect, as when the killer stuffs the mutilated body of Kath Robson with mattress feathers, "like stuffing a chicken . . ., a ridiculous little white frill between her legs."

It becomes clear that Pat Barker is moving into deeper metaphysical waters with this novel; or is it just that she has grown a little more strident? Even the title underlines it: we are dealing here not just with violence against women or social decay, or fear or irrationlity, but with the very wolf at the door -- ingrained, pervasive and contagious evil. In case we miss the point, the book is prefaced with a quotation from Nietzsche, "Whoever fights monsters should see to it that in the process he does not become a monster. And when you look long into an abyss the abyss also looks into you." When Jean, the bravest of the women, finally achieves her moment of Nietzschean revelation, its impact is reduced by the memory of that quotation, hovering behind it like a learned lesson. "Last night I dreamt about him, the man who killed Carol and Kath and the rest. He was standing under an arch of the railway, with his back turned. I went up to him and tapped him on the shoulder. He turned round . . . and I was looking into my own face.

The trouble with overstating the problem is that it exaggerates the difficulty of answers. "Why?" asks Maggie, Where is there "some revelation of good to balance the evil?" The last 30 pages of the book are much weaker that the rest as Pat Barker strives for some such revelation, finding it ultimately in a vision of the natural world transformed, just as she did at the end of Union Street. This time, however, the ending seems contrived, as though written to a formula grown stale.

Blow Your House Down is a courageous and disturbing novel. It would be a pity if Pat Barker continued to allow metaphysics to outstrip her very considerable dramatic gift.