PD James: a master of detective fiction

She is a master of detective fiction - and, at 85, still up to date with forensic science. But PD James's latest novel seems to be an epilogue to her previous stories. Will it be her last, asks Rosita Boland.

Ten minutes into the interview, a waiter arrives with bottles of water. PD James, the English detective novelist, is in mid- sentence, explaining the setting for The Lighthouse, her latest novel featuring Commander Adam Dalgliesh, which takes place on a private island off Cornwall. "The idea was for an island used in a particular way; an island used for a unique retreat, long-established, for men and women who were holding . . ." She pauses.

We wait while a linen napkin is spread out on the table, bottles uncapped, water poured, our welfare inquired after, thank-yous said. Time passes. Then, the instant the waiter departs, James finishes her sentence without missing a beat: " . . . positions of very high authority, either in the state, in the armed forces, in industry, commerce, or in the arts, where they can get away from the stress of ordinary life, leaving behind their protection officers."

I played the tape back later, to be certain it was a seamless sentence, despite being broken in two by a couple of minutes. It was. Very few interviewees can carry a complete sentence in their head over an interruption. Sometimes, they even forget what the question was. Virtually all begin their reply again. The clarity of James's mind in focusing so intently on both the question and her answer is immediately and impressively obvious - and this, if you please, is from a woman now 85.

Phyllis Dorothy James, who was born in Oxford in 1920, has written 17 novels and two non-fiction books. She came to writing a bit later than most, in her late 30s. Her first novel, Cover Her Face, was published in 1962. It featured the detective who has appeared in most of her novels since: a ferociously intelligent man, who is also a published poet and, despite being almost alarmingly self-controlled, impossible not to like. Apart from his ability to solve cases with lateral thinking, courage and luck, Dalgliesh has been remarkable for his inability to sustain a relationship with a woman. James went on record a long time ago as saying that she didn't want to worry about Dalgliesh's love life, so she "rather callously" wrote off his wife by the rather Victorian method of having her die in childbirth.

Before her writing career, James worked for the National Health Service and as a civil servant, first in the police department and later in the criminal-policy department - experiences she integrated into her novels. When her husband, Connor Bantry White (to whose memory The Lighthouse is dedicated), died, in 1964, she raised their daughters, Claire and Jane, alone, turning to full-time writing in the 1970s. She never remarried.

James's beautifully written novels are often set in contained communities, be it a theological college (Death in Holy Orders), a publishing house (Original Sin), a museum (The Murder Room) or a nurses' college (Shroud for a Nightingale). True, they are all murder stories, but they are neither thrillers nor crime novels. The quality of the writing, and the complexity of the characters and the moral dilemmas they face, make James's books far superior to most others in the murder genre.

How does James describe her books? "What I try to be is a good novelist, working within the tradition of the English detective story, so the form is indeed very traditional, and I do use the structure and conventions of a classical detective story," she says. "At the same time, I try to extend the scope of the genre and to write a serious and good novel concerned with men and women and, indeed, with the society in which they live. I think that men and women under the stress of an investigation for murder can often reveal all sorts of facts about themselves which normally would stay hidden. A murder investigation strips away every scrap of privacy, both from the living and the dead, so it's a wonderful way of investigating character and character under stress."

James is small, elegant, charming and warm. About the only concessions to her ninth decade are a hearing aid - recently acquired - and hands that look knotted and veined with experience. Like most people successfully established in their fields, she is refreshingly modest: there is nothing to prove. She is impeccably turned out, in black slacks, lavender shirt and silk scarf. The slacks suit her: somehow, she wouldn't seem at home in a dress. She wears two large and very modern-looking rings, a silver necklace and a plain Swatch.

I don't know why the battery-operated watch is a surprise, but it is, and I keep looking at it. Perhaps because, when you're a writer of detective fiction, people scrutinise you in a different way, themselves looking for clues about your personality and, therefore, an insight into the mind of someone who writes about murder for a living. And perhaps also because, despite James's meticulousness about keeping up to date with forensic science, there is still something very old-fashioned about her characters, an old-fashioned outlook that the watch doesn't match.

Dalgliesh, for instance, when he finally falls in love with Emma Lavenham, an academic, in The Murder Room, declares his love to her by letter - not in person, nor even by phone or e-mail.

James herself writes the first draft of all her books by hand, then has a secretary, who comes to her daily, transfer it onto a computer. There can't be many writers left who still depend on a secretary to type up their books.

"The world has changed so drastically since I wrote my first book, so unbelievably so, and so has police investigation," says James. The changes in technology are reflected in her books: in one written in the 1960s, the ringing of a landline telephone becomes a crucial clue; this contrasts with 2005, when every character has a mobile and police can track the location of each call.

Bigger, global concerns have also crept into the books. Security, including the protection of world leaders and decision-makers, is a key theme in The Lighthouse. Certain of the main characters fall prey to Sars. There are references to bird flu. A James novel is not just a detective story but also a slice of the social history of the time.

In the latest book, Dalgliesh and Lavenham finally unite. "I think I came to a time where he needed to commit himself to a relationship," James explains. "I think he had been an observer of life too long. He was using his job to guard his privacy. But you have to be involved with life properly; otherwise, you lose your soul."

What age does she visualise Dalgliesh as? He is never given an age in the books, although he is promoted. James laughs. "About 42, 43." So, after 43 years of being 43, Dalgliesh has finally been allowed to fall in love again, and so to grow up.

There is a potent feeling that The Lighthouse, in some way, is an epilogue. Ends are tied up. Dalgliesh finally gets his woman. James, though clearly fighting fit, is, after all, at an age by which many people have long retired. And writing a book is a job of work, especially with the kind of technical research that James weaves into her novels. Will there be another Adam Dalgliesh book?

"My responsibility is first to my talent and second to my readers. I can't write a book without a good idea. And, so far, I haven't had one for another book. I'm 85. I would like there to be another book, but if there isn't - if I don't write any more novels - I know I have still produced a body of work I am happy with."

In 2001, she was asked in an interview with the Observer if she believed in God. She replied at the time: "Yes, I do." Given that she writes about the ending of lives, does she believe in an afterlife? "To be absolutely honest, I don't know," she says, looking startled. "I just don't know.

The Lighthouse, by PD James, is published by Faber and Faber, £17.99