In the footsteps of fallen heroes

Pat Barker would be the first to admit that her greatest asset in this year's Booker Prize victory was a fictional character called Billy Prior. The beguiling hero of the magnificent First World War trilogy that culminated with The Ghost Road is a soldier, a working-class lad, cheerful, flirtatious, amoral - and a victim of the final, pointless battle fought over the Sambre-Oise canal in the first week of November 1918. The preponderance of books and memoirs by officers and gentlemen has tended to obscure the fact that the vast majority of those who fought and died in the First World War were young working-class men.

Pat Barker became so obsessed by the character of Billy that she had difficulty in letting him go. She talks about Billy Prior as though he were every bit as real as The Ghost Road's other central characters: Siegfried Sassoon, Wilfred Owen and the army psychologist William Rivers. "The characters would not lie down. I realised it had to be a trilogy when I got to the end of Regeneration [the first of the three] and my characters were still in the middle of a war. I knew then that the therapies at Craiglockhart had to be tested against the events that produced the trauma. And I needed to know what would happen to Billy."

Craiglockhart, the setting for many of the events in all three books, was the psychiatric hospital near Edinburgh that treated traumatised soldiers, whose commonest symptom was hysterical paralysis. They would be given electric shocks, or have radium tubes attached to their skulls. However bizarre, these treatments were thought to work: by 1917, Barker says, 80 per cent of shell-shock cases were back in the front line within a fortnight; their symptoms, if not their basic terror, successfully alleviated.

There can scarcely be anyone left alive who actually fought in the First World War: even a 16-year-old who joined up in 1918 would be 93 today. Why does it still grip our imagination although it ended more than 75 years ago? "The British public is obsessed and traumatised by the First World War, partly because for a long period immediately afterwards, everyone denied that it had mattered. During the Twenties, memories of the horror were being suppressed, which - in classic psychological fashion - created a neurosis about the war. Only with the publication of Robert Graves's wartime autobiography, Goodbye To All That, in 1929, and also the Sassoon war trilogy, did people face up to the horrors. There's still a national - something - about the First World War today; sometimes an orgy of self- congratulation, sometimes a traumatic pain.

"The British have this image of themselves as immensely pacific people: we like to believe that all our wars have been forced upon us. It's difficult for a nation that is proving to be very bad at a great many things not to be proud of something we're very good at, like fighting wars. There is also a nostalgia for the feelings of national unity and shared purpose which war always brings out. People lived very intensively and for many of them, the rest of their lives was an anti-climax. I began to realise that people don't have an unlimited capacity for intense experience. For those who have lived through a war, nothing else will ever register with the same clarity."

Pat Barker herself, at 52, has not lived through a world war, nor has her son - now aged 26 - been called up to fight in one. Where does her own interest in the First World War stem from? "It goes back to my teen years in the late Fifties, though it's only in the last six years that I've been writing about it, and probably springs from something very deep in my personality, as well as childhood memories. My grandfather fought in that war and was bayoneted. As a little girl I was sometimes allowed to put my finger into the hole left by his wound.

"He was traumatised by the war; I was very aware of that. The poetry of Wilfred Owen and Britten's War Requiem were all entwined along with the family history. Yet in my own family I saw that war could also be a positive experience, especially for women. Their lives were often considerably extended by war, by the things they were able to do that had previously been forbidden. In the First World War some women even came under fire, and no doubt felt the same sense of adventure, in the beginning, as many young men. The disillusionment, for them, came more slowly and the bitterness went deeper.

"I went to France with my husband as part of my research for the books. I got a great sense of the scale of death and the waste. I was appalled - not by the number of graves, I had come to the battlefields extremely well-prepared and I had expected that - but by the youth of those who died. So many were 17, 18, 19. I came back and looked at my own son, who was then 19 ... I was also staggered by the memorials with thousands and thousands of names of those whose bodies were never found. Quite by chance, we found the name of my husband's uncle. That was a very moving moment.

"It is the warrior role to defend the group, the territory, and your family, and it's important to realise the good and positive as well as negative aspects of this.

"Yet it may be that our national obsession with the First World War is no longer shared by today's young people - I suspect because they haven't been taught about it. I heard a terrible story from a retired soldier who was taking us round the war graves. All through the Second World War the British graves from the First were perfectly tended and remained immaculate; but just recently there was the first incident of vandalism: a party of British schoolboys spray-painted the gravestones and wrote their names on them."

Back to The Ghost Road ... Is it, I asked Pat Barker - before her Booker win - is it her best book? "I think it may well be, though it isn't the book I'm fondest of. That is Regeneration, which I call my `unloved' book. It got some very good reviews but not a lot of recognition or sales. Also, I do very much stand by my first three books about the lives of working-class, provincial women. But some themes, characters and situations are more highly valued than others in literary circles. You could write better and better about women in the back streets of Middlesbrough and still not be mentioned in the same breath as Salman Rushdie."

Well, she did, and now she is: which will surely be a source of quiet satisfaction to Pat Barker.