A Wire that runs through history

Christmas Day, 1985, the homicide section of Baltimore Police Department. A young crime reporter wanders in with a bottle of cheap whisky. It's not a busy day: no murders, just the odd shooting and a stabbing. So there's time to talk. Drink, talk, and drink some more. "You know," says the homicide sergeant, "if someone sat around here for a whole year and wrote a book – man, that would be some story."

All fans of The Wire know what happens next, but he tells the story all the same. How that quote became a year spent with the 36-man murder squad; how the year became a book (Homicide: A Year on the Killing Streets), which became a TV series, Homicide: Life on the Street; how Homicide… led to The Corner, with its true-life stories about drugs-ravaged inner-city Baltimore; how the two of them led to The Wire; how The Wire led to its writer, David Simon, rounding up the best writers in America. Like, for example, Richard Price.

Price has his own stories for the Main Tent. The Wire hardly figures in them, because it was already series three when he started writing for it, because he only wrote five out of the 60 episodes, and all the characters were already formed in other people's minds and so he was really just being a jobbing writer, fleshing out someone else's plots with his own dead-on dialogue.

Price seems shy, diffident, ill at ease. The event's chair, Al Senter, doesn't seem to have read much of his work. It's a bad pairing, like having Jimmy Young chatting to Vladimir Nabokov.

So for a while, in the audience, there's a sense of unease. This could, they feel, be one of those car crash Book Festival events: a great writer being interviewed by someone who doesn't realise who he is or why he's a great writer in the first place.

And then Price reads. He doesn't set anything up, just tears into the opening for Lush Life: four cops in an unmarked car driving around the Lower East Side – once as heroin-ridden as David Simon's West Baltimore corners, now gentrified beyond recognition – looking rather desperately for anyone on the make in the early hours of the morning: desperately, because firstly, any criminal worth the name can spot an unmarked police car as easily as if it were lit up with fairy lights and secondly because all that gentrification means that there are no criminals worth the name living there in the first place.

This is the novel (as Senter didn't mention) that Barack Obama took away to read on holiday last week. It's a revelation, crackling with the kind of quick-fire dialogue that makes you think of Elmore Leonard, yet an Elmore Leonard who also gives you just as vivid a sense of place, even when that place is, as here, a crazily condensed, multicultural mix.

On this side of the Atlantic, we just don't have writers like either Simon or Price. We don't have writers who wander round our cities' ghettoes like Simon did in West Baltimore for The Corner and Price did in New Jersey in his research for Clockers, trying to understand and explain an alien drug-dealing subculture; not writing anything for months on end, just making the connections, earning the trust, and finally showing that those lives aren't quite so alien after all.

That matters because cities matter. The government may ignore them – as Simon and Price's next project, about New Orleans after Hurricane Katrina, will almost certainly show in close-up – and the media may gradually be pulling down its inner city shutters, but as long as there are writers like Simon and Price it's hard to give up hope. Just don't ever, warned Simon, think the internet is ever going to tell you what's really going on there (or, come to that, anywhere else that matters).

Oddly, it's not such a great leap from Simon and Price to Tristram Hunt talking about Friedrich Engels and "the greatest friendship in Western political thought" – his relationship with Karl Marx. After all, what was Engels doing in Manchester in the 1840s except finding out precisely how the "shock city of the Industrial Revolution" actually worked and what life was like for those trapped on the bottom rung of society's ladder?

One of the great ironies of history, of course, is that even those people who are the most certain about the tracks it is running on invariably get it wrong or behave in ways that seem hard to reconcile with their politics. For all his knowledge about Manchester, Engels's philosophical disagreements with Chartist leaders meant that his brand of revolutionary socialism was all but ignored in Britain. If anything, he seemed far happier riding to hounds with the toffs of the Cheshire Hunt.

Strip out the myths we impose on the past, forget that we know what happens next and apparent wrong turnings or inconsistencies start making sense. But as Hilary Mantel and Adam Thorpe both agreed, in a fascinating discussion on historical fiction, the novelist has to go even further than that.

So little is known about Thomas Cromwell, the subject of Mantel's latest novel, Wolf Hall (deservedly the overwhelming favourite for this year's Man Booker Prize) that, she said, "the only approach to him is through fiction. There are plenty of books about him but none with a human being inside. And the advantage of being a novelist is that you can carry on working at the point where historians have to stop."

What she – and Thorpe, whose latest novel imagines Robin Hood as a sociopathic murderer who is also a leader of a heretical sect – means by that isn't that the novelist should depart from the known facts.

But when those facts lead into a thicket of ambiguity, the novelist can carry on moving forward with their historical characters, remembering all the time that even Thomas Cromwell and "Robin Hud" didn't know all the facts either, "but were all acting on imperfect information, walking into the dark with a little flickering of a rush light to illuminate their own lives."

Whether in the mean streets of West Baltimore, the multicultural mix of New York, the slums of Victorian Manchester, or the terrifying court of a Tudor king, a little flickering of the empathetic imagination can clearly go a long, long way.