THIS isn't the first 9/11 film and won't be the last, but I doubt if we'll see a better one than British director Paul Greengrass's documentary-style feature about events surrounding the fourth hijacked plane.

Because United Airlines flight 93 took off half-an-hour late, passengers on board knew through phone calls home about the attack on the World Trade Centre and correctly surmised they were en route to a suicide mission too.

The film ends as some passengers and attendants attempt to overpower the hijackers - including one claiming to have a bomb strapped to his body - and retaking control of the aircraft. The terror of those on board United 93 is intercut with activity in the air traffic control and military operations rooms, as the wider tragedy of 9/11 unfolds.

Greengrass's documentary style - and use of unknown actors as well as real life flight crew members, controllers and other personnel in the cast - gives the film an urgency and realism that makes it all the more horrifying.

The movie has the pace and tension of a thriller but, at the back of your mind, is the nagging realisation that this is one movie where there won't be a happy ending.

Running Time: 111 minutes

Rating: Four Stars