Beyond Bogotá

The Colombian writer Juan Gabriel Vásquez had been struggling with a story set in the second world war for three years when it struck him that the thing which had been holding him back from writing was in fact the best reason for trying to tell the story. He had been trying to follow the usual advice and write about what he knew, but suddenly he realised that "not understanding something is the best reason a novelist can have for writing about it.

"The novels I like, the novels I like to read, and the novels I would like to write are novels of investigation, novels of inquisition," he says, "novels that work as a tool to approach a certain understanding of something that wasn't clear before."

First published in Spanish in 2004, Los Informantes (The Informers), arrived in the UK earlier this year, but the idea for the novel came from a conversation he had with a German Jewish woman back in 1999.

"She told me during this dinner that her father, who had arrived in Colombia fleeing Hitler, was almost thrown into this confinement camp because he had a German passport and thus could be dangerous for the security of the hemisphere," he continues. "Now that's a situation, I thought, with an immense grey area. Morally, philosophically it was an ambiguous situation, and ambiguity is the great territory of the novel." Not that the second world war isn't full of moral certainties, he adds, it's just that when those certainties collide, they create morally complicated situations which almost demand exploration by a novel. "The thing novels are good at is exploring those ambiguities in those situations we usually see as clear cut."

"I don't want to get too fundamental about novels," says Vásquez as he leans back in his chair and laughs, "I have that tendency."

The Informers is built in a series of interlocking sections, with each section undermining the section before as the narrator investigates an old betrayal. It's a novel he says he couldn't have written had he stayed in Colombia.

Born in the Colombian capital, Bogotá, in 1973, he left South America towards the end of the war between the drug cartels and the government in 1996. It was a complicated decision to leave, driven partly by the practical difficulties of living in what was one of the most violent cities in the world, and partly by a desire for geographical distance, for perspective.

"Perhaps the strongest reason was much more difficult to explain," he continues. "I got the idea that I had to leave to become the kind of writer I wanted to become. It's a kind of Latin American tradition to leave your country to be able to write." He cites Rubén Darío, García Márquez, Vargas Llosa, Carlos Fuentes, Julio Cortázar - "all of those great names made themselves as novelists abroad. It's almost a kind of need we have."

The first stop on Vásquez's literary pilgrimage was Paris – the city where Ulysses, the book which made him want to become a novelist, was written – where he studied at the Sorbonne. In 1999 he moved to Belgium, and then shortly afterwards to Barcelona, where he now teaches Spanish literature to American students and writes, reviewing fiction as well as publishing two novels in Spanish. His second book, Historia secreta de Costaguana, was published last year, when he was also nominated as one of South America's most exciting young writers, the Bogotá 39. For Vásquez, Barcelona is a city set apart from the rest of Spain, a city where he now feels very much at home, enjoying the "impunity that comes with living abroad" and the sense of distance from his birthplace.

Living 5,000 miles from Bogotá offered Vásquez the perspective he needed to explore his country's troubled past. After his years of grappling with the story at the kernel of The Informers, he finally came up with the idea of following a journalist as he investigated a murky episode in his father's life.

"I had already spent some months interested in the way historical conflicts often take the shape of a father and son conflict," he explains, "because a conflict between a father and a son is a conflict between two different ways of seeing the world, between two different positions in the historical landscape. Sons resent their fathers because of the world they have received, fathers resent sons because of what they have done with the world they were given. So I thought that an archetypal story about the relationship between a father and a son was the best scenario for a story about finding the truth in your past."

It's a tale of repeated betrayals as Vásquez's journalist breaks the confidences of those he befriends in pursuit of an explanation of his father's disloyalty. The novel circles around a moment of treachery which took place in 1943, beating its wings against the impossibility of knowing someone else's mind until a bravura turn at the close of the novel, where Vásquez dramatically reasserts the novelist's power within the fictional world he has created.

"In a way it's taking revenge against a very hard fact of life," he says. "For my narrator, that final passage allowed him to do something that really is not possible in life, and that's one of his grievances. We are unable to get a the unique, absolute version of our past, that's an impossibility, and that's something that should bother every novelist."

For Vásquez, novels are "perhaps the best tools we have invented, as human beings to deal with our past – to deal with the act of remembering, to deal with what it means to remember, with what it means to try to forget". He mentions Ricardo Piglia, WG Sebald and Aldous Huxley as he argues that everything we see is shaped by our cultural heritage, and that the novel is uniquely placed to examine the contradictions that result. While poetry is inevitably filtered through a vision of the world which it is impossible to suppress, prose fiction can be as unbiased as Flaubert.

"The great invention of the novel, as we know it since Cervantes, is neutrality," he continues. "It's the first human narrative that can explore more than one side of the same question in a completely neutral way, without taking sides ... if the novel respects the legacy of Cervantes it will be neutral, compassionate, inclusive."

He shrugs as he admits to being one of those "strange, annoying beings" who has their bookshelves at their fingertips, always ready with a telling example or a timely quotation. It's an ability which shapes his own writing at every level, every sentence composed in a chamber of echoes which resounds with the ghosts of what has gone before.

This deep engagement with what Vásquez calls "my tradition", makes him acutely conscious of the literary territory writers have already colonised – their styles, techniques and obsessions - but he is also keenly aware of how new developments open up different spaces for the writers who come after to explore.

"Is there such a thing as progress in the arts?" It seems a ridiculous question at first, he continues. "To say that Beethoven is better than Bach is completely absurd. But Bach did discover things, did invent things without which Beethoven would not have been able to write what he wrote. In the same way, some things Joyce did in Ulysses opened doors, opened possibilities for the rest of the 20th century, and without that such traditional novelists as Gabriel García Márquez couldn't have worked."

For Vásquez the only reason for a novel to exist is to "go where no one has gone before". The writers that interest him are like chameleons, discarding the hard-won lessons of the novels they have already written to carve out new ways of writing with each successive book.

To write the same kind of novel again and again would "bore me to death," he says. "The name of the genre suggests it. We have to do things that are new, we have to take new approaches to human experience, to our human condition, the things that worry us every day, otherwise there's no going forward."

· Juan Gabriel Vásquez is appearing in coversation with Michael Ondaatje at the Hay festival Segovia on Thursday September 25