Fay Weldon: The time of her life

Laughter and tears, science and superstition, fact and fiction still mingle magically in Fay Weldon's work - and life. Susan Jeffreys meets the irrepressible she-devil

"Nothing makes women happy for more than half an hour," she says. "It's Darwinian. It's survival. We always have to be worrying about the men, keeping off the tigers, fearing for the children. Women can't afford to be happy for long. That's why they keep getting out of bed to make sure they've put the fish in the fridge and locked the back door. It's best to acknowledge there's no way out of this trap." She laughs again, good and loud, and the men, and scattering of women, doing business look across and seemed pleased for her.

The pursuit of happiness, and of goodness, are on her mind at the moment, as she's working on what sounds like a very strange book indeed. It's a how-to book of exercises to improve the soul. Some are simple, she says. Old-fashioned, grandma things such as: "Be good and you'll be happy. Be happy and you'll be good." I look up from scribbling in my notebook, slightly alarmed. Is Weldon going to go into the mottos-on-cushions business? You never know with her. She's put her hand to many a thing in her hard-working past. "But you don't have to be as good as all that," she reassures; "you can sleep with your best friend's boyfriend once, but not twice. Once, you can get away with, but twice, you just don't." Phew. Stuff the cushion business then.

"You are what you are: that's what I want people to understand in this next book, but you can manage to impose some order upon your baser desires, to which" - and here she gives me a disquieting look with her clear blue eyes - "you are bound to succumb one day." I'm looking forward to the Weldon advice book. It's going to knock the bloody Little Book of Calm right off the shelves.

Right now, Weldon has a novel out, with the enigmatic title She May Not Leave (Fourth Estate, £12.99). It's an unsettling book, in that deceptively simple way that so many of her books are. Actually, it's not quite a novel: she has had a run of writing books in which fiction and autobiography leak into each other. Auto da Fay was almost an autobiography, with bits of novel creeping in. Mantrapped was almost a novel that would take a sudden veer off into autobiography. She May Not Leave is lightly scattered with Fay facts. Now, though, she feels she has almost worked her way through that seam.

The leaking of one character into another, a Weldon trademark, will remain a constant. In She May Not Leave, Agnieszka, a calculating au pair, slowly takes on the clothes, and much, much more, of Hattie, the woman she works for. In other books, characters have been cloned; swapped faces, bodies, even souls. Why does this theme of interchanging crop up so much in her work, and so often among women?

"Women change their natures," she replies. "If they tell their life stories to their boyfriends, then tell it again three months later, it's a totally different story, but they believe it when they're telling it and they feel strong in their identity. Other women seem much stronger in their identity than I am. I always wear the same clothes." I thought I'd glimpsed that sharp but somehow surprising black leather jacket somewhere before.

It's not just the characters that leak in a Weldon book. The boundaries between science and superstition also seem full of holes. Weldon's hands are square and practical. She'd been deep in a copy of New Scientist while she waited for me, yet Auto da Fay is full of strange coincidences and spookiness; there's always something a little fey about Fay.

"You have to live your life as if it was practical, as if ectoplasm didn't exist. I was reading New Scientist just now, but I might just as well have been reading my horoscope. You can do both. It's all right to read your horoscope, but you'd be mad to live your life by it." Time bends and loops in Weldon's fiction, and in her autobiographical work: "It's a great mistake to think of time as linear. It's practical to behave as if it's linear, but if you look at it from outside, from above, you can light on it at any time. I always think it's odd when people talk about being reincarnated in the future. Why not in the past?"

A strong female line runs through her fiction, and her own life. Men were distant, vague figures in the matriarchal household in which she grew up in New Zealand. In She May Not Leave, Hattie, employer of the manipulative au pair, has a daughter called Kitty, who is close to her Weldon-like grandmother. Weldon likes the way the female line runs strong, though often hidden, through history. "They found a 4,000-year-old bog man in Cheddar, then they DNA-ed and found a direct relative, living close by. He was teaching history in a grammar school in Cheddar. The awful thing was, he was the last of the line because he had no sisters, and no daughters. The mitochondrial line stops as soon as you get two succeeding generations without women. Then it's had it. That's it - the line stops."

Fictional DNA, though, can march on into the future. "I might write about what happens to Kitty," she says. "Set something into the future. It's difficult, doing that. You don't want to get bogged down with all the details." She already has a line of books written or mapped out, so she's taking a leap across time here, but after all, it's not linear.

Her prose, never flabby, grows leaner with each book. It's impressive what she achieves with so few words: "The simpler, easier and quicker you can do it, the better. After all, you're only filling in the gaps in the reader's head. It's probably part of my advertising training. It's important not to torture your reader."

Despite the leanness of the prose, there's something gothic in her writing. Nasty things go on in Weldon books, particularly when the settings are bucolic.

I mention an aside in She May Not Leave, about the use of ground-up corpses in animal feed. It came from a time when she was running a farm in Somerset. "I was feeding the poor sheep this stuff. The animal-feed people were very odd, very secretive. There was always something shifty about them. There was a horrible, horrible smell and no proper safety rail. People would fall into those terrible, terrible bone-grinding pits. It was like hell. You'd drive up in your car and ask, 'What's in it?', and they'd look at the feed, and they'd look at you, and you thought you'd be lucky to get to your car and out the gate alive."

She's done with agricultural work, though she may deadhead the odd rose. She lives now in Dorset, but has not yet set any book there. "The landscape hasn't imposed itself yet, but it will." She spends her days writing, reading and playing solitaire on her computer.

She went from pen and ink to computer, without benefit of typewriter, and thinks computers have changed the way people write: "Writing by hand is much more convoluted, and much more implicit." The computer has freed her writing up. They're leaky things, though, computers - they should behave like logical machines but we all know they don't. Behind those screens, order and chaos mix. That doesn't worry Weldon, who likes working both sides of any border.

"I love my computer. I really love it. You get to know their little ways. The one I have now will, if I'm writing a screenplay, read my script out in different voices. It will even try to read all my spelling mistakes, very bravely. I'm very fond of it." Again, she laughs loud enough for heads at other tables to turn. We have both definitely had more than our Darwinianly allotted half-hour of happiness.

Let's not run away with the idea that there's something flaky about Fay Weldon. She has raised four sons, often as not on her own, supported members of her extended family, and written more than 20 novels. Then there are the plays, the scripts, the non-fiction, the magazine articles and the sitting on panels, the judging of books and all the other business of a 21st-century woman of letters. Why carry on? Is it all just, as she said in Mantrapped, to pay last year's tax return? "No. That's an excuse really. It's what I do. It's a continuum."

Biography: Fay Weldon

Born in 1931, daughter of a doctor and romantic novelist, Fay Weldon was brought up in an all-female household in New Zealand after her parents' divorce. She studied at St Andrews University, worked in advertising, and published her first novel, The Fat Woman's Joke, in 1967. Other fiction includes Remember Me (1976), the Booker-shortlisted Praxis (1978), Puffball (1980), The Life and Loves of a She-Devil (1983), The Cloning of Joanna May (1989) and Wicked Women (1995). She has written many plays for TV and radio. A memoir, Auto da Fay, came out in 2002; and Mantrapped in 2004. This month, Fourth Estate publishes She May Not Leave. Fay Weldon CBE, who has one son from her first marriage and three from her second, lives in Dorset.