Imagine us, sitting in a Charlotte Street restaurant. Simon Chinn, who is a young producer, wants to make a film about Philippe Petit, the man who walked across the space between the Twin Towers by wire. I know that we must make this film, because it will be the best homage to New York and its inhabitants after 9/11. And somehow I think already, yes, the film will win an Oscar.

Although I am an Oscar tart, the awards do have a practical significance. Despite critical acclaim, documentaries are a beleaguered genre. It's hard to get a documentary recognised and watched outside the circle of buffs and film-makers that crowd the growing number of documentary festivals. An Oscar for a good film means that documentaries are taken seriously by people who don't normally watch them. And these are the people I wish to reach.

We do have setbacks along the way but, on the whole, everything goes smoothly. By the time I saw the first cut of Man on Wire, two years ago, I knew that the director, James Marsh, had made the film of a lifetime. I didn't go to the Oscars ceremony; instead I stayed up. But by this stage the award appeared a formality. I was glad on behalf of all the people who'd worked on the film, but my real emotion was relief. The award could make it easier to fund not just a successor, but many more films as ambitious.

About the first, I've been proved right - Simon Chinn and James Marsh's next film was indeed easy to fund. In other respects, however, I have a more melancholy message. Finance for big, ambitious documentaries among distributors is drying up. Elsewhere, money is hard to come by. There have been cuts in documentary budgets almost everywhere, and one of Britain's most reliable patrons, Channel 4, is under pressure. And we have to hope that documentaries will emerge unscarred should there be any further shrinkage of the BBC.

• The writer is the editor of Storyville. Man on Wire is on BBC2, Sunday at 9pm