Eternal student of extremes

Though his prose is as surgically precise as ever in his new novel, Ian McEwan, like his work, has become less intimidating and more humane, as Eileen Battersbydiscovers

Ambivalence is a territory that British writer Ian McEwan understands with a chilling clarity. That, and the thin line between the sinister and the vulnerable; as well as the invariably violent and often sexual obsessions and anxieties that make up modern life. It is Tuesday, the fourth anniversary of the American/British invasion of Iraq, not that the citizens pushing past the slow-moving tourists on London's streets appear to be thinking much about the war. Most of us have taken to sighing - funny how anger burns itself out and settles into irony. McEwan shudders slightly at the reminder of the date and says "oh is it?" with a mild half-smile. As the son of a career soldier, he knows a good deal about conflict. He was born in the aftermath of the second World War, grew up at a succession of military camps and has lived through the threat and reality of global upheaval.

More than most, McEwan understands the moral ambivalence of war, to engage or to ignore, and it was this ambivalence that framed his 2005 novel, Saturday. In it, neurosurgeon Henry Perowne wakes up on his day off and is preoccupied by a squash date, not the anti-war protest march that is about to paralyse London. Perowne, a doctor who convincingly thinks like a doctor, not a novelist, is guilty of self- absorption - as are most people.

As a character, self-satisfied Henry is ambivalent, because people tend to be, just as McEwan's characters tend to be real rather than heroic.

In common with Martin Amis, a fellow former nominee on the Granta Best of Young British Novelists list, McEwan has more than fulfilled his early promise. Hitting 59 this year, if not quite yet a literary elder statesman, he has amassed an impressive body of work as well as the wisdom that comes with experience.

Throughout his career, which began in 1975 with the short story collections, First Love, Last Rites, and was followed by a second, In Between the Sheets, he has balanced the imagination of a scientist with the instincts of a psychiatrist through controlled narratives that are dark, frightening, funny and uncomfortably accurate about human behaviour and relationships. Humankind in his early fiction was decidedly unpleasant: consider the couple in The Comfort of Strangers (1981) enjoying the cruel, ritualised death of their victim as witnessed also by the dying man's drugged girlfriend. Yet his characters and his stories became, from The Child in Time (1987) onwards, increasingly, movingly humane. He agrees it was an important book for him.

"It really is the ultimate nightmare, losing your child," he says. Born of a recurring dream, or nightmare, it is a terrifying book in which a child is abducted in a supermarket and simply vanishes. The book triumphs through its subtle tone of desperate yet quiet helplessness.

It was a landmark work for McEwan, a new humanity emerging as the almost pornographic cruelty of the earlier work gave way to a deeper exploration of trauma and guilt.

"I was slow to mature . . . in the beginning, there was too much Kafka, and" - slight pause - "too much Freud." Even so, McEwan's prose was always mature, exact and precise, as he says, without a hint of pomposity.

"A writer has a moral responsibility to language," he says. Humour is another element. "There always has to be humour - I think it's so important and I've felt it was there in my work."

The shift from European metaphysics to American realism was decisive. McEwan reveres John Updike and is irritated when he sees him being accused of writing "too well". It offends McEwan's scientific logic. "How can someone write too well? You either write well, or not well enough."

It makes sense, but then everything McEwan says makes sense. He is a clear-minded, down-to-earth character, non-literary in his conversation and apparently greatly amused by his intense younger self. For all the blackness and his interest in "extreme states of mind" as well as extreme behaviour, there is always humour. Even at its most intense, his new novel, On Chesil Beach, about a stillborn marriage, is as funny as it is sad and devastatingly believable.

In person, he seems relaxed, contented and funny, a good talker. Sitting in a Soho restaurant, he praises the work of John McGahern and remembers the man, whom he liked. "I thought Memoir was wonderful. He was very intelligent, very funny, sophisticated. I remember having lunch with him." McEwan looks around. "I think it was here, in this restaurant."

Later, he announces with certainty, "It was here, that lunch with John McGahern. I never realised he was so ill," he says. Seamus Heaney, "a real poet", is another Irish writer he admires, and he refers to an essay in The Government of the Tongue, "and that other Northern poet . . . Paul Muldoon".

WHEN I FIRST interviewed McEwan 20 years ago, when Thatcher ruled the show, he was clever, aloof and intimidating, but now he seems more at ease, friendlier, his eyes are softer.

His second marriage is happy. "I have two children and two stepchildren and I think good things can happen by chance," he says. He met his second wife, Annalena McAfee, when she interviewed him. "I only wanted to do a couple of interviews, and there had been so much fuss about my life, I decided to do an unlikely one, the Financial Times, and that's how we met. I liked her."

In common with Amis, McEwan's life - which includes media intrusions into his private life, a marriage break-up, tussles over custody, a ridiculous accusation of plagiarism and, only recently, a newly discovered older brother - is the equal of his fiction. Unlike Amis, McEwan has always been well-reviewed and has won the Booker, for Amsterdam, admittedly one of his slighter books by comparison with outstanding works such as The Child in Time (1987), The Innocent (1990) and Atonement (2001). The last of these, the first third of which is a masterclass in fiction writing, is "soon to be a movie", McEwan says, with equal measures of amusement and dread.

He has never seen John Banville's famously negative review of Saturday, but is aware of it and mentions how well that book did in England. How strong is his British readership? "It's okay; and okay in the States, good in Germany, and I'm big in Italy but not so much in France."

McEwan has been translated into more than 30 languages and now knows what it is like to look at a foreign-language edition of one of his books and not know which one it is until he opens it. "I can recognise them from how they look on the page."

Amis and McEwan, survivors of the Granta class of 1983, is an interesting pairing. In the shadow of the great JG Ballard, they - Amis the stylist and McEwan the psychologist - represent the best of British fiction and both have matured as artists.

While Amis came from a literary world, McEwan did not and is open about how much books influenced him, "first the Europeans, then the Bellows, the Updikes, the Roths - that last Roth book, Everyman, is very good . . . I look to the Americans. Martin has Bellow, I have Updike - I love the Bech books."

McEwan reacts to books as a reader, albeit as one who knows how they are constructed. "Books are like houses," he says, going on to describe how that vivid set-piece opening sequence in Enduring Love (1997), in which several people grapple with a hot-air balloon, was actually written when he was halfway into the novel, a study of obsession and the breakdown of trust. Atonement, which is partly about guilt and deception, is also about storytelling and the relationship between what is imagined and what is true. It is also about other writers, including Virginia Woolf and Elizabeth Bowen, with a bow to Waugh's Brideshead Revisited.

Important to McEwan has been his sense of being an outsider, his lack of social tradition. If he doesn't seem particularly English, it is because he doesn't feel a strong Englishness. "I grew up all over the place in army camps, and my father was not a member of the officer class. He rose through the ranks. We didn't have that officer thing." Class is something McEwan has always understood and he knows what it is like to equate even food with class - "I didn't know what an aubergine was until I went to university and ate these exotic things at the homes of my friends." For most of his childhood, cheese was cheddar - mozzarella came later.

He looks at class with interest, not defiance. Almost by the way, he remarks of the character Edward, the young man in the new book who marries the violinist daughter of a Bohemian upper-middle-class family, "all that stuff about his discovery of the different kinds of foods they eat, that was me, it's fairly autobiographical".

His use of class as a device was also highly effective in Atonement. It is not a Big House novel, the large country house having been built by new merchant money, not old landed wealth. Class, war and history are enduring major themes for McEwan, who has always been an ideas writer.

There is nothing particularly self-absorbed about him. Instead he speaks about his fiction with the detachment of a surgeon who remembers the particulars of each case, while his now lived-in, clever, bespectacled schoolboy's face lights up when he is discussing the work of other writers, and most particularly music. Genuine excitement for McEwan nowadays is anticipating the next concert at the Wigmore Hall. Books and music dominate his conversation and, as he is friendly with many writers, he is always hearing about books.

HIS WRITING BEGAN quietly. In his third year at Sussex University, where he read English and French, he wrote a play "and I submitted it to the drama society". McEwan seems to enjoy telling stories as well as writing them, and sets the scene. There he was, the aspiring writer who set off, in hope, to a meeting at which the drama society were due to discuss new works it had received.

"I sat there, thinking what it would be like if they began tearing my play apart," he says. "But it never happened. They didn't even discuss it."

He laughs at the memory of it. The persona of the student still lingers about McEwan. Currently working on a libretto, he wrote another for Michael Berkeley's oratorio, Or Shall We Die?, as well as television plays and the screenplay of The Ploughman's Lunch, all of which have given a further dimension to his writing experience.

His new novel, On Chesil Beach, is, as he says, "a short novel" and it is also very good. It appears simple, with a young couple who have just got married arriving at the hotel for their wedding night.

"I wanted to write a short novel - I think short novels are very good - and see what could happen if something went terribly wrong," he says. "The characters in this book are very young, only 22, and they hardly know each other. Edward finds himself in the position of being able to make everything right or to destroy everything with a gesture. And he does destroy everything and only sees his mistake when it's too late."

In ways, On Chesil Beach is a companion novel to Amsterdam, although in that engaging morality tale, with its nod to Auden, the characters are much older. It begins at the funeral of the central character, Molly Lane, as two former lovers discuss her and her husband George, "the sad, rich publisher who doted on her and whom to everyone's surprise she had not left, though she always treated him badly".

On Chesil Beach is about youth. Edward's impatience leads to Florence's flight and his rage. It is a convincing work in its grasp of a female fear of sexuality. McEwan left a deliberate vagueness about the young woman's relationship with her father.

"I have enormous sympathy for Florence," he says. " I also think she is very brave. And I am sympathetic to Edward."

His treatment of Florence's dilemma - her belief in love and romance, and her dread of the physical - is extraordinary. McEwan seems thoughtful and says: "Who decided that a female character could only be written by a woman?" Again there is no defiance; he is making a point.

This ability to evoke a female sensibility was also apparent in Atonement, in the character of Briony. Last year saw McEwan facing charges of plagiarism about the historical material in that novel, despite the fact that he listed Lucilla Andrews's No Time for Romance in the acknowledgements. The fuss quickly petered out as many writers, notably Thomas Pynchon, came to McEwan's defence and argued the need for historical accuracy.

"[The Innocent] was the first book I researched," McEwan says. "I decided to cycle along the Berlin Wall with a friend. I couldn't believe the way the West Germans acted like it wasn't there. They saw it as a political embarrassment. Imagine ignoring something that literarily ran through houses."

The idea still amazes him. He regrets that The Innocent was overshadowed by one macabre episode, in which a character is dismembered and put in a suitcase. "That's the thing everyone remembers," he shrugs. It is a shame, as it's a fine novel.

He has met Pynchon. What does he look like? McEwan bursts out laughing. "Like an American college professor, and he doesn't like being described as a recluse. He walks about, goes shopping. He just doesn't give interviews."

• On Chesil Beach, by Ian McEwan, will be published by Jonathan Cape on Apr 5, £12.99