Violent stepfathers come in different shapes, as Andrea was to find out. Peter, red-faced and reeking of engine oil, had once been in the merchant navy and he liked to run a tight ship. The girls (soon baby Sarah came along to make it three) weren't allowed to play with Lego unless they pressed the bricks together without making a noise. They weren't allowed to accept treats when visiting relations ("You want everyone to think I don't feed you properly?"). Above all, they weren't allowed to tell when he bashed them up.
Most of the bashing was reserved for their mother, who wore dark glasses to hide her shame and swore blind to friends that he never laid a hand on her daughters. It wasn't true. Everything about Andrea and Laurie exasperated their stepdad - their braininess, their artiness, even their dusky Mediterannean skin, which got them teased at school for being "Maltesers" and "Pakis". The punishment for any hint of self-assertion was a slapped face, a boxed ear, a head banged against a wall. There was also the time when Peter's fingers slid under the blankets to try to touch Andrea between the legs.
Canada - emigrated to on a whim - promised to relieve the pressure. There was space. There was sun. There was Auntie Penny, with her ice creams and barbecues, teaching the girls about home comfort. But Peter blew the family lolly on drink and fancy cars, and the marital rows grew worse. Their mother's only concern was to stop her daughters witnessing the blows: whenever Peter was about to clop her, she'd send them out of the room.
Fleeing back to England, they set up house without him. Andrea - a "little Einstein" - flourished at school and her mother resumed work in a geriatric home. Relations warned them off seeing Peter again: "You need that bastard like you need a hole in the head." But wheedling and intimidating by turns, he wasn't completely off the scene until arrested (the police finally intervening) during a last cataclysmic attack. Andrea's mum had a good run after that, going to clubs and fizzing with life - until another bastard showed up.
With his Spanish guitar, gold Jag, Cuban heels and wads of money, Terry looked more like a shining knight at first. The family moved up a notch, shopping at Asda rather than KwikSave, and acquiring a colour TV. Where exactly the money came from no one asked, until Terry departed for a spell in prison. It was when he came out that the abuse started: unable to go nicking, he took up hitting. Like Peter, he had a vicious resentment of the girls getting above themselves, sneering at Andrea's love of "poncy books" and (in a scene of gut-wrenching Dickensian cruelty) preventing the self-taught Laurie from pursuing her dance career. Battered and collusive, their mother didn't resist him.
By this point Andrea was old enough to think unthinkable thoughts - to wonder whether certain women might not be attracted (and attractive) to violent men, for instance, and to protest at being reminded that Terry's problems lay in his own violent childhood ("Why do we have to pay for what his mum and dad did all that time ago?"). At 12, she was already weighed down with adult responsibilities - cleaning, ironing, babysitting her younger sisters, keeping the house together, mothering her mum. Cautiously rebelling, she tried the usual adolescent things - fags, clothes, boys, bunking off. But books were her only real refuge: Anne Frank's diary, Tess of the D'Urbervilles, Dylan Thomas, Larkin and Plath. Books got her writing ("A poem was a box for your soul ... the place where you could save bits of your self") and proved to be her escape-route too, leading to middle-class friends, a sixth-form college and Oxford. It's as she leaves for Oxford - having won a place there while coping with her mother's depressive illness and her stepfather's threats to kill himself - that the book ends.
Tales of domestic violence can be dispiriting. But Once in a House on Fire, which reads more like a novel (Sons and Lovers, say) than a confessional, is full of energy, wit and a child's wide-open gaze. Perhaps it's no coincidence that among those whose help Andrea Ashworth acknowledges is a poet, Mick Imlah, for the book is bright with metaphors - the brace she wore as "a fence between me and romance", for instance, or industrial chimneys "that rose up like kings and queens on a chessboard", or the "sky-blue marbles" of a baby's eyes. If she had waited until middle age to tell it, her story would surely have been more introspective, and maybe more moralistic. Writing it as she has in her twenties (itself quite an achievement in a literary culture where youthful precocity isn't expected much before 40), she goes about it briskly, with merciless detail and smiling insouciance ("Smiler" was her nickname at school), letting objects, dialogue, and quotes from songs and poems do the work of conveying feelings. The book's great strength, as it watches life crumble apart, is its solidity. The texture of a whole era is there in names and brands: B&Q and Do-It-All, Gloria Gaynor and Barry White, Nightmare on Elm Street and The Krypton Factor, Penguin biscuits, Tetley's tea and Radio Two.
Much more than a tale of wicked stepfathers (though there is enough about male brutality here to make any man despair of his own sex), Once in a House on Fire is a story about survival, almost old-fashioned in its belief in Literature, capital L, as a means of salvation. Hence Andrea Ashworth's emphasis on her schoolgirl achievements: she isn't showing off but tracing each footstep out of the labyrinth. And even if she were showing off, good luck to her: she escaped the fire to write a remarkable book.