9/11 is a classic example of cinema verite, a sort of realist documentary, in this case of New York firemen as they battle against one of the most extraordinary events of world history. It's all tiny, unobtrusive, hand-held video cameras, often betrayed by the poor quality of most of the filming (and by the director, Naudet's hand frequently wiping the screen).

In this film, you get to know most of the firemen - Tony Benatatos, the rookie (or 'probie', in NY fireman vernacular), the Fire Chief Joseph Pfeiffer (who finds he's lost his brother later on) and a few others. There are studio interviews with most of these people throughout the film, just to emphasise the personal, reflexive nature of the events. The build-up is quite dramatic and well-done, particularly the passing-out ceremony at the Fire Department, with a few useful swish-pans and a sort of dialectical editing of the rather limited filmwork (just like Rob Reiner's A Few Good Men). Tony looks proud.

The viewpoint and camera angle is usually from amidst the firemen, which is interesting and there is some excellent footage from inside the lobby of WTC1 while Pfeiffer and his team plan what to do next - this is classic cinema verite. There is also the eery, haunting sound of the occasional human body crashing against the portico outside. It is then that an increasingly forlorn Fire Chief Pfeiffer realises that his task is desperate and probably hopeless - and this is before WTC2 collapses. You have to give credit to Naudet for knowing which faces to film and at which moment.

The sound of the neighbouring WTC2 collapsing is so awfully sad, poignant and terrifying that you realise what an ordeal this is for the firemen. From the lobby, it looks, feels and sounds like the end of the world and the poor firemen look so utterly bewildered and frightened. You hear an enormous rumbling, trembling maelstrom - like that of a giant, monolithic beast slowly falling to the ground after being so mortally wounded - the neighbouring tower has collapsed yet the fire team remaining in WTC1 are oblivious to this event. Where is the communication?

This film is captivating yet the narration is amateurish and should have been avoided - cues like 'this really was a day like no other' or Naudet's frequently banal pronouncements like 'you could see fear in everybody's eyes' and 'I knew Tony was freaking out'! The film is really just one long video diary. There are no pictures from higher up the building where some of the firemen have gone. Imagine this film blended with CCTV footage from some of the rooms higher up or some of the news coverage from the day. The effect would be greater. You could even combine this story with that of Mayor Giuliani and, perhaps, the famous Cornishman Rick Riscorla who literally was many floors up acting the hero.

I don't see much of a propaganda element in this film, as some reviewers suggest. This film is no Triumph of the Will, by Riefenstahl. Some time later the firemen drape the American flag over a nearby, surviving building overlooking what has become Ground Zero. So what?

There are also some moments of dubious camerawork; for example, who is holding the camera when the two Naudet brothers are reunited back at the fire station? Is it staged?

There is an excellent finish, very much in the traditon of the excellent French director Alain Resnais (Hiroshima mon amour), with two strips of light reflected in the water, shimmying.

Sentiment: positive