Writers portraying past times often find it hard to take off their contemporary spectacles. Helen Dunmore doesn't have a problem with this, apart from one major lapse that weakens the ending. For the most part A Spell of Winter which moves from the Edwardian era through the First World War, is deeply and fittingly unfashionable. The characters frequently kill small furry creatures, and a sense of hope and content can result from the shooting of a duck on a perfect morning, its body making a "light sweet sound" as it is pulled from the ooze.

The melodrama of the last few pages becomes inevitable.Funny, tragic and wonderfully perceptive, this is a book to be treasured, for the sheer quality of its writing and for its honesty. Around her dwindling figure, her companions iron their boyfriends' shirts and worry about pregnancy, seething with fertility-panic. We remember that her mother's idea of cooking was to slap corned beef on a plate and quarter a tomato; we remember the stolid grossness of Karina's greed; we are sobered by Carmel's suppressed despair at losing her lover, by the poverty of her life. Carmel's anorexia creeps up on us, as it does on her: only when she collapses on the stairs does the silver thread of its snaky progress into her soul gleam back into the petty meanness of her beginnings. And together they both progress to London, locked in that bitter friendship that the shameful secrets of a shared childhood confer even on enemies.The narrative drive of the novel accelerates steadily towards the end Food, sex and appearances become dominant. But steadily and insidiously their lives diverge from the apparent reality; faith and virginity are quietly lost. They are urged to yearn for thick tights, stout shoes, bulging briefcases.

Her mother is "quarrelsome, dogmatic and shrewd" (Mantel's trios of rhythmic adjectives are reliably instructive, incisive and apt). Feverishly and embarrassingly, she embroiders gambolling lambs on her daughter's school frock, with large and calloused hands, "made to hold a rifle, not a needle." Her father is feeble, devoted to jigsaw puzzles and assuring her that if ever she's in trouble she cannot count on him. In class, she sits next to the baleful Karina, mainly because "odd as my outfit would be, Karina would be wearing something odder."These two get scholarships to a convent - not the Antonia White school of sadistic pietism, but a place smelling of incense and custard, where girls are taught to develop social consciences: a training-ground not for life's officers, says Mantel with deadly accuracy, but for its foolish volunteers. Ah, we might say knowingly, here we have thinly- disguised autobiography, a rite-of-passage to be endured by every young ambitious writer and her audience But we would be wrong.