BOOK / Ralph among the hot water bottles: Sue Gaisford meets Hilary Mantel, whose new book wonders how to do the decent thing

In 1976 two women were talking at a bus-stop about a recent spate of vandalism at the youth-club. One said: 'They stole my skeleton, you know,' and the other replied: 'Good job it wasn't a full-sized one.' By sheer good fortune, Hilary Mantel was listening and from this overheard, gnomic exchange grew her second novel, Vacant Possession. That's how it happens with her. Some little trigger is pulled, she starts with a bit of a story and works away on what it's all about: a novel appears.

Her new book, A Change of Climate (Viking, pounds 15) began with another eavesdropping. It was 'one of those mundane, everyday tales of a man who'd gone off the rails in mid-life and left his family. So you think why? - and you realise that a chain of events lies behind it, and then everything else that's been pre-occupying you for years tends to feed into it, and you write it.' Sounds easy, but the finished product is a work of exquisite craftsmanship that asks enormous questions. Carried along on the crest of her elegant style, which combines an astringent wit with compassionate understanding and the narrative tension to banish sleep, the reader gradually realises the book turns on the issue of how little we are in control of our lives, how much at the mercy of forces outside ourselves.

It is about Ralph Eldred, a good man who tries to do the decent thing. His East Anglian family are evangelical fundamentalists who see 'no need to enquire into God's nature; they approached Him through early rising, Bible study and earnest, futile attempts at humility'. When Ralph appals them by developing an interest in geology and evolutionary theory, his mother confronts him with 'that frayed sigh that only mothers can perform' in a successful, wicked ploy, whereby his sister will be allowed to study medicine only if Ralph drops his own ambitions and goes instead to Africa, with his new bride, to run a mission.

That nasty bit of blackmail is the first of four secrets in the story. The jealous guarding of these secrets, or their attempted suppression, leads to a destructive misery that threatens to overwhelm Ralph, his wife Nina, their children and the people they love. Sorry if this sounds unduly mysterious, but to reveal more of the plot would be to deprive you of the pleasure of picking up the little clues and hints dropped artfully through the text, from Anna's determined, excessive, scrubbing of a bloodstained floor near the beginning, to her son, Julian's, reading of a tombstone near the end.

This tombstone is a real one, set in the floor of a small Norfolk church. It commemorates Frances Hibgame, 'who died 19th of December 1736 aged 10 yeares, 5 months, 2 weekes and 1 day'. Hilary Mantel came upon it by chance, and it gave her just the exemplum she needed for Julian to be shown how much people have always loved their children, whatever conventional wisdom dictates. She smiles, remembering the day she discovered it, because it illustrates so neatly what might be called serendipity, or her own chaos theory: that we never know where things will lead. She could so easily have stopped at another of those tiny churches and never found a way of enlightening Julian.

She is a warm, humorous woman with beautiful wide, clear blue eyes. Her voice carries a touch of Derbyshire where she was born, and where she set her very funny and successful novel Fludd; but she lives now beside a large common in Berkshire. When she was first married, she went with her husband, a geologist, on an aid project to Botswana, an experience that gives a real authenticity to the African scenes in the new book.

They lived through some harrowing experiences there, but, like Ralph and Anna, found that there was no difficulty in not talking about them when they came back. 'People just didn't want to know. You'd want to tell them about the night you crashed your car, alone in the bush, about the day the dog was deliberately poisoned, the night the housemaid was raped, but all they'd say is 'Been away again?'. Your life has acquired a huge, operatic dimension, but they are just happily humming along to Top of the Pops.'

Some, of the shocking events in the book happened to her, others she learned about from African law reports or friends - 'I knew someone who was stabbed by a burglar. He said he felt a big heavy blow, not a cut, and it didn't really hurt, but he lay on the floor, certain that he was dying, not wanting to be disturbed - it's very useful to have friends who've been stabbed.' Either way, Mantel writes about these things with a conviction that keeps you reading even as your hands shake.

Her hero Ralph returns to Norfolk. It is 1980, and the window of Boots the Chemist boasts a 'razzmatazz of vitamin supplements and glucose tablets, a come-and-get- em pyramid of Kodak films and an alluring display of hot-water bottles'. He fills their draughty house with a succession of lonely inadequate refugees from psychiatric hospitals and orphanages, known to his children as Sad Cases. He administers the family trust and occupies his days with a succession of small good works. Hilary Mantel is not particularly pleased at the suggestion that this is how Dorothea lives out her life, commendably, at the end of Middlemarch. But then she admits to loathing George Eliot, having had to teach Silas Marner to African children. 'Mind you, they had a good deal of sympathy with her moralistic attitude. They sorted out Molly Farren as if she were a Botswana teenager - 'Well look, Madam, this is the way of it: you start off going to a beer-drink, then you're smoking dagga, then the next she'd be on this laudanum business - should never have gone on the beer-drink'. They thought Eliot was quite right to terminate her existence.'

Anyway, Ralph's good works are not enough. All they do is to prevent him from having to face the really big question: why did God let terrible things happen to me? A line from the Book of Job, quoted at the start of the novel, points in the same direction. Hilary Mantel mentions Muriel Spark's book The Only Problem. The only problem, she says, is no less than the whole problem of human suffering. Can God be all good and yet all-powerful? Or, as Ralph's Uncle James puts it, if it is chance, can it be malign? If it is malign, can it be chance? 'I could write about this to the end of my life,' she says, 'whether - how far - in the face of suffering, one can maintain faith in a benign deity. I suppose in a way I wrote the book to find out if I believed in God. I didn't find out. I'm still in a fog. But I told a story and I've been able to look at some of the dilemmas. I think, as an author, it's your job to keep asking questions and to create a climate in which people are thinking about these things.'

I liked Ralph, and so does his creator. His integrity, kindness, courage, his dogged determination to do his best must surely be admirable? But no, she is a little dismayed to learn that the men who have read this book loathe him, to a man. They see him as a wimp. Even her husband? Well, yes. But then, he must be a manly man. On their bookshelves is his vast collection of rare, early, unbowdlerised Biggles books, where the hero drinks, smokes and cusses with carefree abandon. Mind you, the later, over- corrected ones are fun too. In one of them, Mantel recalled, Biggles, accompanied by Ginger, lands his little plane in the Yukon. Together they swing into a saloon full of desperate prospectors. Biggles bangs his fist on the bar and demands a Bovril for himself, and a malted milk for Ginger.

She's very funny about macho men. 'I'm sure they do have imagination and sensitivity and a whole range of good qualities: it's just - from day to day - where do they keep them?' Her next novel will tell us what she really thinks about feminism. She hates the Mrs Thatcher model, where women become pseudo-men and take on their worst characteristics, but she does quietly worry about what happens to all the bright girls, why they make so little of their lives.

When she was a child, Hilary Mantel's favourite writers were Robert Louis Stevenson and Charlotte Bronte. Thinking about them now, she muses: 'If you could combine the sheer momentum of Kidnapped with the psychological acuity of Jane Eyre, wouldn't you have the perfect book?' Few novelists today come as close to it as she does.

(Photograph omitted)