The British novel is back in the stocks - and this time it is the ubiquitous Andrew Marr who is throwing the wet sponges. The impish political editor of the BBC is surely exhibiting early symptoms of that fever of irrationality and omnipotence that seems to afflict judges of our leading literary prizes (I should know: I was a jabbering victim myself when I judged the Booker in 1997). Marr used the recent announcement of the shortlist for the Samuel Johnson Prize for Non-Fiction to complain about the mediocrity and imaginative paucity of the modern British novel compared to the range, readability and urgency of so much non-fiction.

Now, Marr is a clever chap, but his views on the novel ought not detain us for too long - because he has never exhibited an active, rigorous engagement with modern British fiction, as either a critic or a writer of fiction. In any event, by seeking to generate faux controversy, he was merely fulfilling the duty of every chairman of a literary jury.

More problematic, and perhaps more pertinent, are the views of Dale Peck, the talented young American critic-novelist. Reviewing Julian Barnes's feeble Love, Etc in the New Republic, Peck suggested that the elite of British fiction - Barnes, McEwan, Amis, Rushdie and so on - had systematically "ruined" the British novel. "The idea that Julian Barnes is the successor to Sterne is nearly as unbearable as the idea that Margaret Drabble is George Eliot's heir," he wrote. "And how has Fielding been watered down into A S Byatt and Defoe bastardised into Jeanette Winterson." As for Ian McEwan: "His novels smell worse than the newspaper wrapped around old fish." Zadie Smith? "Too Oxbridge."

Peck continued: "I do not mean to suggest that there are not any good writers in Britain . . . merely that the writers who have been anointed as the propagators of the great tradition of British fiction seem to be intent upon destroying all that is good in that tradition. Virginia Woolf thought that reading Ulysses was like watching a schoolboy pick his zits in public, but if her alternatives were Will Self and Tibor Fischer, perhaps even she would jump on the Julian Barnes bandwagon."

Reading Peck, one wonders what it is about the modern British novel that compels so many critics to traduce it? Why, when confronted with, say, the latest easy read from Nick Hornby or the latest soft-focus romance from Sebastian Faulks, do Marr, Peck and other serious readers recoil in disappointment? Why do the repeated criticisms of the British novel - that it is clever but empty; that few, if any, writers can do character and narrative; that most have lost confidence in the fictional possibilities of England - resonate so peculiarly?

Part of the problem, I suspect, is that fiction in Britain long ago ceased to be an act of moral inquiry. "There was a time," V S Naipaul has written, "when fiction provided discoveries about the nature of society, about states, which gave those works of fiction a validity over and above the narrative element . . . No longer . . ."

In this, Naipaul - and, by implication, Marr - is right. The unparalleled popularity of narrative non-fiction shows how readers crave the kinds of representations of contemporary society that were once provided by the great novels. In particular, they are fascinated by the quirky side stories of history that were once often lost or neglected in works about great men and empires. As a result, biography and history have moved closer together, creating in the process a new form, a kind of non-fiction novel in which the traditional concerns of the novelist - interiority and consciousness, motivation and agency, character and narrative, invention and story - are appropriated by the alert writer of non-fiction.

If there is real excitement in contemporary writing, it is found not in entirely invented narratives, but in hybrid forms combining history, reportage, autobiography, fiction, travelogue and the essay in new and unexpected ways, as best exemplified by the work of W G Sebald, Claudio Magris or Emmanuel Carrere.

While I no longer believe in something called the English Novel - merely that there are English novels, both good and bad - I am still concerned by the failure of so many novels - mine included - to bring urgent news of our times, as J M Coetzee did in Disgrace, his tough parable of post-apartheid South Africa; or as Philip Roth did in his trilogy about the corruption of postwar American society.

Race and gender, the failure of the left to remake society, the hegemony of the media, the triumph of nihilism, the fetishisation of celebrity and sport - there is no shortage of urgent subjects out of which to make fiction. But perhaps it is hard to be Nietzsche, Dostoevsky or Celine in the 21st century; hard to be existentially committed in a country as mired in mediocrity as ours.

The truth is that affluence and a benign political culture have curtailed invention, and that relative calm has coincided with a less radical will to experiment. We long for a novel that brings "news" of our times, as Dickens, Wells and Conrad once did. But how few writers there are who can do this - and how culturally impoverished we are as a result.

The writer is NS literary editor