The first film to dramatise the events of 9/11, opens in Britain on 2 June 2006.
United 93 depicts the events of 9/11, when four American passenger planes were hijacked by al-Qaeda terrorists. Two of the planes crashed into the twin towers of the World Trade Centre, one was steered into the Pentagon, and the fourth one - United Airlines Flight 93 - crashed into a field in Pennsylvania.
The 33 passengers - among them one Japanese student and the German Wine Institute Representative Christian Adams - seven crew and four hijackers died.
The film focuses on what is likely to have happened on Flight 93, arguing that in light of a phone call and cockpit recorder evidence it would seem that the passengers on board managed to foil the terrorists' apparent plan to crash the plane into the White House in Washington.
One of the stars is the Hertfordshire-based German actor Erich Redman who has lived in Abbots Langley since 2001.
He portrays the German passenger Christian Adams, who urges his fellow passengers to comply with the terrorists, arguing that that was historically the best strategy for survival. Meanwhile, most of the other male passengers are gearing up to attack the four Arab hijackers.
Erich, whose previous credits include "Saving Private Ryan", "Charlotte Gray" and "U-571", told us what we can expect from the film, and all about the unusual filming process at Pinewood where the actors playing the passengers and terrorists were kept apart and the idea of a conventional screenplay was abandoned in favour of a series of intense rehearsals and improvisation to get the atmosphere that director Paul Greengrass wanted.
By all accounts this is a very impressive film?
Erich: Yes it is a very impressive film! There's been a lot of controversy around it but when people go and see the film they will realise that it has been done tastefully and with a lot of dignity. It's a very worthwhile film to go and see.
Although everyone perished on that flight, there's still a lot of evidence of what happened isn't there?
Erich: Yes - there is a lot of recorded evidence. We have the transcripts of all the phone calls that were made between the passengers and their loved ones or the police on the ground. The CIA gave us most of those transcripts and the actors playing the characters who made those phone calls were pretty faithful in delivering those very same lines that the passengers spoke on the day.
You play a role of a German passenger. Did he try to alter the events on that flight?
Erich: Well, we don't really know that because he's not known to have made any phone calls. However, his was an unusual situation, he was the only European on board, all the others were Americans and one Japanese, so he was kind of isolated in that way.
And as a German he must have been aware of the 1977 hijacking of a Lufthansa plane which ended in Mogadishu which had a happy ending. The plane landed, the terrorists asked for money and then they were overwhelmed by German special forces. So after that, Germans constantly repeated that if that ever happens to you, whatever it takes just comply with them and things will be taken care of on the ground.
And I think that on that day, on 9/11, he must have thought of that. It must have crossed his mind that if he interfered something horrible was going to happen, so it was probably best to comply and I'm sure he passed that information onto the other passengers.
Is it true that the actors playing the passengers were kept away from the actors playing the terrorists until filming began?
Erich: Yes - the four actors playing the terrorists rehearsed in Camden and we rehearsed in Pinewood and we didn't meet them until the first day of filming. There was a rumour that they were coming to Pinewood for a fitting but they were kept away from us and we were never in the same room.
It is a very interesting technique, the director wanted us to be wary of them. If you rehearse together you become friends and you bond with them to some extent and so the fear that the director wanted to create on the plane wouldn't have been as effective.
How did it feel when you eventually met them then?
Erich: It was weird, you knew that they were actors but there was definitely the emotion of they are the enemy and we have to be afraid of them. You'd brush past them on the way to the tea machine and there was a real uneasiness.
To a certain extent I think they also felt alienated from us as well so there was a lovely atmosphere of what I would call gentle hostility - so I guess the director achieved what he wanted!
The whole film used improvisation rather than a conventional script. Did you enjoy working in that way?
Erich: It was interesting but daunting. Personally I prefer to learn my lines as it makes you feel more secure. And it was difficult especially as English is not my native tongue, I was scared I would fluff it or not be able to find the right words. You are acting on your toes and it definitely sharpens the mind!
But it's also exciting because there is a real liberty. When you get a conventional script and you don't like the lines because they don't quite fit what you are doing, the director can get very precious about them and you can't change them. But in this you have the freedom to change them and you feel like the co-author of the film because you've had a hand in the dialogue.
The actual hijack scene was shot in 'real time' - how did that work?
Erich: The actual sequence from the hi-jacking to the plane going down took about 35/40 minutes and we filmed it as one take - but 14 times! It was very gruelling as there was no air conditioning or anything like that. It was a very long take and the emotions that you had to conjure up every time were very draining.
In the end the director cut events from different takes because he had in his mind a sequence of what he wanted to happen but he didn't tell you it because it wouldn't look like it was natural. For example, someone heard that two planes had hit the World Trade Centre and this information needed to be passed to the back of the plane. He needed to cut between the 14 takes to make that happen.
It was quite an experience, very tiring and very traumatic because we weren't doing a comedy. For the whole take, 14 times, you had to feel that you were close to death and that you were going to die and that is not a nice emotion.
There were concerns from the families of those who died on the plane when the idea of the film was first mooted, but since the screening of the film they've all said that they are happy with it, haven't they.
Erich: There were a lot of dissenting voices especially in America, and especially in New York, about the film being too early and all the newspapers were giving the director and the film makers a lot of flack.
However, they made a complete U-turn once they'd seen the film. The director Paul Greengrass [Bloody Sunday, The Murder of Stephen Lawrence, Bourne Supremacy] has done similar things to this before. He knows how to tackle sensitive issues and he infuses the film with so much integrity and so much respect for the people who perished that no one could say that this has been exploitative or commercial or even a Hollywood action kind of thing. He did it very well.