THE ARTS: It's been seven years since 'Last Orders'. Now Graham Swift has a new novel. It was well worth the wait, writes Arminta Wallace

Graham Swift sits eating a chicken salad, apparently unperturbed that it has been seven years since he produced a book. The last time he produced a book he won the Booker Prize, but still. Seven years between Last Orders and The Light Of Day? What took him so long?

He shifts, allows another few inches of his lanky frame to unfurl over the edge of his chair and shrugs. "I'm not someone who produces a book a year," he says. "The gaps have been four to five years in the past. My time was rather taken up by Last Orders, it has to be said - not unhappily, but it was a while before I could get back to myself, to concentrate. Then I had to find the new book. That takes a while. And then there was the not unfamiliar process of not getting it right the first time, of rewriting and just having another go. Several years go by . . ." He shrugs again, smiles. "I don't see myself as someone who . . . well, I don't want to write a lot of books."

Swift's first novel, The Sweet Shop Owner, appeared in 1980. But it was his third, Waterland - an elegiac meditation on history and the mysterious landscape of the Fens, the flat, low-lying former marshes of East Anglia - that propelled him into the literary firmament. It earned him rave reviews and a raft of prizes: the Guardian Fiction Award, the Winifred Holtby Memorial Prize, the Italian Premio Grinzane Cavour and a Booker shortlisting.

When he finally lifted the Booker, it was for a very different novel. With its duck 'n' dive premise - a group of Londoners assemble to scatter the ashes of their dead friend - streetwise dialogue and interwoven narrative voices, Last Orders has the feel of an ensemble piece.

Swift's new book retains the gritty realism and multilayered narrative. Like its predecessor, it places a death at the centre of the action; this time, though, it's a murder. This time, too, there is just one narrator, George, a private detective who's not above getting physical with his more attractive female clients.

When Sarah Nash hires him to follow her husband and his mistress to Heathrow Airport, it looks like an easy job: just follow, observe and let the client know if the mistress boards the plane alone. "Money for old rope," George tells himself. Except Bob ends up dead, Sarah ends up in prison and George ends up visiting her once a fortnight.

Or, rather, that's where the book starts. The Light Of Day is suffused with mystery; suspense makes the story tick. Yet as Swift is quick to emphasise, it is not a crime novel. If anything, it turns the conventions of crime fiction upside down. "We know who the killer is, but we don't know what happened," he says. "George certainly doesn't know what happened, because he was only a partial witness to some of the events, and the reader gleans information from his intense internalised imagination."

Ultimately, the book's sense of mystery derives not from the mystery of the murder but from the underlying mystery of death - and, even more, of life. "It's about the discovery of things inside ourselves," says Swift. "I mean, through his relationship with Sarah, George has discovered things within himself which he never knew were there, just as Sarah has discovered terrible things in herself which she couldn't have guessed at before. I don't see this book as a detective story. It's a story in which the principal character is a detective.

"So there's a different draw, a different tension from, 'Who did it?' And I think that's one of the challenges that I was up against: how do you provide momentum and suspense and tension when the basic outcome is there from the start?"

How Swift does it is one of the great mysteries of contemporary fiction. His books are almost laughably readable, his characters achingly ordinary, his language stubbornly everyday. The secret is in the telling: razor-sharp timing, effortless handling of multiple time frames, immaculate observation. So how does he do it? He must be tired of the question, but he doesn't show it.

"I work by feel, by instinct. I just sort of know when to do something. And I trust myself on things like pace and timing, the essential techniques of narrative. I think by now I sort of know how to do it," he offers. It is the kind of politeness often thought of as quintessentially English. It encompasses reserve, restraint and understated integrity: qualities, as it happens, that play central roles in Swift's portrayal of character. There is a moment in The Light Of Day when George, having gone to the cemetery on the second anniversary of the murder, to put roses on Bob's grave, wonders what to do next.

"My feet are cold. How long do you give it? A minute? Five? I said to myself: Just do it, lay the flowers - go. But it's not that simple. How long is right, how long is fair, when you only come once a year?

"Put down the flowers. Now beat it before the hate, or anything else, rises up. The seethe in your throat. But it's not up to me anyway. I'm here for her, for her sake. Her agent. How long would she give it, if she were here?"

Eventually, he sits down on a nearby bench, musing about his parents, his former life as a policeman and, of course, about the murder. Some 43 pages later, he's still there. "Gone twelve. Enough. I get up from the bench. I've given it time enough. Time enough for respect, time enough to say I didn't hurry it." Even though there was nobody to see whether or not he did.

Where did it come from, this highly developed sense of fair play? It is probably no accident that George's creator grew up in a London still traumatised by and in thrall to the second World War. "There were things called bomb sites," says Swift with a rueful smile, "though I wasn't necessarily aware when I was very young that they had actually been caused by bombs being dropped out of planes.

"But my father was a pilot in the navy, so there was the direct experience which my parents had, which was like something pretty close, just over my shoulder. And then there was all the glamorisation of the war: the Boy's Own version, which was constantly being recreated in comics and so on. It was a valuable lesson for a writer of fiction, because you need both a sense of truth and a sense of how myths develop. The second World War was really my great history lesson - and, although I didn't know it at the time, I think it formed me as a writer."

Waterland, too, is steeped in history, narrated by a history teacher. Its more discursive style and lengthy descriptive passages make it very different from the books that preceded and followed it, however. Did Swift set out to make it so?

"Even as I was writing it," he says, "I thought it was more ambitious and more confident than anything I'd done, so clearly it was a very important book for me. And it's a book I'm very proud of, very fond of. But I haven't ever written another book like Waterland and don't think that I ever could or would. It's quite - I don't know how to put this - a wordy book. And, for me, quite a showy book. Since Last Orders I've gone away from that. In Last Orders I found a new sense of language, a new way of using words, where I trust much more in the power of ordinary language.

"Familiar words and familiar images, the sort of common currency we all use, for me the challenge is to make that into something extraordinary. To make ordinary words do something marvellous is, for me, much more interesting than to write a big paragraph of showy prose."

The language of Last Orders was particularly praised for its authenticity. Was it something he worked out aurally, having listened to the rhythms of the Londoners he grew up with, or was it a visual, on-the-page construction? He nods at the word aurally. It was, he says, an instinctive process.

"I can't remember exactly how it worked now, but there must have been a moment when I realised that this book must be written this way, in this sort of semi-speech, though not a documentarytranscript of what might actually have been said.

"I mean, there is artistry in it. But once I'd crossed into it, made the decision, whatever it was, I could forget about it, and it came quite naturally. It was also very liberating. I learned a lot. It was a great discovery, that these Bermondsey characters had a lot in them. And it was my job, as an author, to show what they had in them.

"We all have in us more than we readily show or find the words for, and the novel is partly about finding those words without destroying the authenticity or the veracity of your characters."

The same, he adds, is true of The Light Of Day. George uses ordinary language but thinks extraordinary thoughts. George, needless to say, would put it slightly differently: "Detective work." Swift remarks of his own profession: "It's mostly graft and slog, but there are times when a light comes on in your head."

The Light Of Day is published by Hamish Hamilton, £16.99