Thomas Sutcliffe: Towering thought in a clear blue sky

There's a telling moment in Man on Wire, James Marsh's lovely film about Philippe Petit's wire-walk between the twin towers of the World Trade Centre, when the man himself is describing the danger of the stunt. "What a beautiful death," he says dreamily, "to die in the exercise of your passion." Halfway through that sentence Marsh cuts to an image of a passenger jet flying over a city. The implication is unmissable. It's the film's one acknowledgement that there would come a time when other young men would converge on the twin towers with a spectacular stunt in mind, when a passionate obsession with this American landmark would end in its destruction.

As it happened I'd just finished reading Joseph O'Neill's novel Netherland when I saw Man on Wire and I was reminded of a literary equivalent of Marsh's glancing allusion. Netherland largely takes place in a post September 11 New York, and close to the end of the book the narrator finds himself at JFK, preparing to fly back to London. "The aircraft went into reverse; taxied; rumbled innocently out of New York's clear sky," writes O'Neill. Why "innocently", though? Because after September 11 the combination of clear skies and jet planes can't automatically be assumed to be innocent.

It turns out that this feint towards September 11 is tuning the reader up for a more direct contemplation of New York's loss on that day. Netherland conspicuously avoids looking directly at the twin towers or the gap they left behind them. Until the very last page, that is, when the narrator recalls a trip on the Staten Island ferry. As the sun goes down and the city lights come on, the passengers are dazed by the spectacle, "a world concentrated most glamorously of all, it goes almost without saying, in the lilac acres of two amazingly high towers going up above all the others". Almost goes without saying, but not quite – and this delayed sighting of what the novel has until now turned away from is extraordinarily effective, a blend of hope and melancholy foresight and regret.

It's a good example of how potent the twin towers have become as an image – one with such fierce gravitational pull that it can only be admitted at the last moment, after you've established your entitlement to use it, or which can be glimpsed only out of the corner of the eye.