Lavinia Greenlaw: Testament of middle youth

At the age of eight, Lavinia Greenlaw jumped through a fastened window while running away from her mother. She was in a friend's house. "There were three French windows and I knew one was open but I chose the wrong one," she says. "I hit it so fast that when I landed I only had two cuts on my knees. The thing I remember most was how glass bends before it explodes. I remember being mid-air and held. It felt like the world was giving me a chance to catch up with what was happening."

Greenlaw used that slow-motion leap at the end of her first novel, Mary George of Allnorthover - her teenage heroine crashes through glass to escape a fire. She later revisited the incident in her excellent short poem "The Falling City". While her new novel, An Irresponsible Age (Fourth Estate, £15.99), contains no such stunts, the characters seem similarly suspended between two states, numbed by another kind of shock.

Juliet Clough and her adult siblings are coming to terms with the accidental death of their brother. The Cloughs appeared in Greenlaw's debut novel, living in the same village as Mary George. Now they are grown up and settled in London. It is 1990. "I was interested in the period between the 1980s and the millennium when things were in a state of hesitation,"Greenlaw explains. "It seemed a good period in which to explore the notion of a family suddenly being compelled by change and not knowing how to handle it." She also wanted to consider "how people can remain children in their own heads when they're in their late twenties and early thirties, even when they have children, are married, have jobs."

Juliet, Clara, Carlo and Fred are frozen in their allotted roles, still behaving in ways they should have outgrown. Because they can't bear to address Tobias's death, they distract themselves, embark on hopeless affairs, disappoint each other.

Greenlaw understands the dynamic of large families, being one of two sisters and two brothers, close in age: "When the four of us get together we fall into place." She adds: "One of the things that sustained me through my childhood was a sense of identity with my family. It provides a kind of machinery. You think you can dip in and out and come back to it. But when your parents split up or your siblings go away, suddenly the machine stops and you have to become your own machine."

It's no surprise that Greenlaw applies an industrial image to something so organic. As a poet, her work shows a fascination with science and technology, time and space. Although she is wary of romanticising science, co-opting it into her poetry always seemed natural.

Not only was her father a doctor; one brother trained as an engineer, her second has a PhD in astrophysics and her sister is an immunologist. "So, I'm very much the village idiot", she says, laughing. It was a household where literature, art and scientific ideas were all discussed avidly. Six years ago, the National Endowment for Science, Technology and the Arts granted Greenlaw a three-year-fellowship. She has also been the Science Museum's resident poet and hasn't shied away from extraordinary commissions. She was asked to write a series of poems on mathematical concepts like the impossibility of the square root of minus 1. Recently, she wrestled with the theory of relativity for a poem commemorating the centenary of E=mc2.

Both Greenlaw's poetry and fiction use autobiographical elements. Her parents, seeking change, quit London in the 1970s and plumped for a village south of Chelmsford. Greenlaw assumed life would be the same "but with trees and fields". She got a shock. Sent to the local comprehensive, she looked different and spoke differently from everyone else. Added to which she had a peculiar name. "I spent seven years just wanting to get back to London."

And 1973 was a year of power-cuts. The "absolute black, countryside night" was something Greenlaw had never before experienced. When she suddenly became acutely shortsighted too, "It was as if every aspect of my vision was closing down." She smiles. "Short-sight has really formed my character. I don't expect to notice things around me, so I remain quite within myself".

Yet her vision can be laser-sharp, her work displaying a talent for moving between the abstract and the keenly observed. Weather, landscape, the natural world are all exquisitely evoked.

Light is a constant preoccupation for Greenlaw. In the new novel it "shoves" and "bounces", but on a drab winter morning, "The movement between London night and London day was more like a prevarication than any clear shift." In the poem "Blue Field", light mesmerises. Greenlaw became inspired by trips to the Arctic. "You get this amazing twilight where everything goes blue", she says. "I felt very, very alive there."

How different from her experience of Essex with its flat landscape and open skies. "Parts of Essex are wonderfully beautiful," she says, "but parts are just dead, somehow. I did feel subdued by it." Much of Greenlaw's adolescence involved waiting hours for buses or trying to hitch lifts. "I think of Essex as a place you can't get out of easily."

During that period Greenlaw read her way through her father's shelves of American and Eastern European poetry, and wrote too. Salvation came from an unlikely source. "I can remember going on a school trip to Basildon shopping precinct - which must be the greyest place in England - and seeing the cover of the Sex Pistols' Never Mind the Bollocks, this lurid yellow and bubblegum-pink cover. The word 'bollocks' had been taped over but what shocked me was not the word but the colour - it was electrifying. In Essex. I couldn't believe it."

With her freshly-dyed pink and black hair and "dead men's suits", Greenlaw was frequently mocked in the street but felt liberated by her new identity. Some years ago, she did a reading in Chelmsford and several of her old mates attended. "There was a definite clanking of chains as they came up the stairs," she says, laughing again. "They asked me if I was still with the boy I was going out with at 16."

Greenlaw wanted to capture this era in her debut novel. Two recollections triggered it: the vault through the window, and staggering across frozen fields to a party. "They were very physical memories which I thought would be a poem. And then this figure appeared, this girl Mary, and I thought - it can't be a poem, because she's a character."

For the writer, the different demands of prose and poetry soon became apparent. While Greenlaw can't compose a poem on screen ("It's too immediate and fools you into thinking it's finished"), she can write prose that way and "push on with it, however painful. You can't make a poem arrive. You have to wait for it to come." She edits everything with a pen: "I need to be writing to be thinking."

Greenlaw thought it was important to find a prose style "not too dense and - dread word - poetic." When someone commented that her novel wasn't a poet's novel she was delighted. "I've always wanted to tell stories and my early poems were quite laden with narrative."

In poetry, the poet is often the character. Does that make the poetry more personal? She pauses. "Probably, yes. A poem conveys an experience in the form of sensation. It's concentrated; to be read over and over. It took me a long time to get used to the fact that you can hold a poem in your hands all at once while the novel is something you have to travel through. I was unnerved by that loss of control and perspective, which is partly why it took me eight years to write Mary George."

An Irresponsible Age isn't exactly a sequel; as a story, it stands alone. Juliet, a walk-on in the first book, stuck around in Greenlaw's head. Here, Juliet launches into an affair with the handsome, older Jacob, a writer whose strong wife looks after him even though they are separated. Juliet sums him up as the type who refers to his "wireless" and uses words like "quiddity" in conversation. He looks blank if anyone mentions popular television but always manages to namedrop terrifically hip bands. His is a carefully contrived artlessness.

Absence is a recurring image in this novel, from Juliet's PhD ("Framed Departure: the Empty Metaphor in Post-Iconoclastic Netherlandish Art") to the white spaces in the A-Z where London's Docklands are under development. The Cloughs, of course, are defined by Tobias's absence. "When somebody dies you are supposed as a family to pull together but we're often blown apart by these things," says Greenlaw. She wanted to show how death affects us, "how protected we are before that moment." Everything trivial seems to vaporise. "It's an exalted state. We think we're going to learn from it, will never go back to operating on a surface level but we do."

Will there be a third book about Mary George and the Cloughs? Greenlaw reflects. "I've a feeling I'm going to look at those characters again ten years from now, when they're in their forties". As we get older, our lives may become increasingly locked down but, "However much we think we see what's coming, we really don't."

Biography: Lavinia Greenlaw

Lavinia Greenlaw was born in London in 1962. When she was 11, her family moved to Essex. After studying at Kingston Polytechnic and the London College of Printing, she worked as a book editor and later an administrator at the South Bank Centre. Her first poetry collection, Night Photograph, (1993) was shortlisted for the Whitbread and Forward prizes. The title poem of her second collection, A World Where News Travelled Slowly, won the Forward Prize for Best Single Poem. Minsk (2003) followed. Her debut novel, Mary George of Allnorthover, came out in 2001 and won France's Prix du Premier Roman. Other work includes plays for BBC Radio 4, libretti and her second novel, An Irresponsible Age, published by Fourth Estate this week. She lectures at Goldsmiths College and lives in London with her 18-year-old daughter.