Natalie Portman stars as Evie, a young woman who finds herself confronted by the feared secret police, or 'finger men', out in the streets after curfew. She is promptly rescued from their salacious advances by a strange fellow in a cape and wearing a perpetually grinning Guy Fawkes mask. Hugo Weaving introduces himself as 'V', and explains to Evie how his primary motivation for such gallantry is as much about revenge against a corrupt political system as it is about altruism.

As their relationship develops, Evie discovers some interesting things about her dead parents - who were both persecuted by the State for their political beliefs. At first she is appalled by V's plan to carry out Fawkes' centuries-old plan (for real this time), but as strange events transpire she becomes more convinced of the need for some kind of radical political activism.

McTeigue agrees that recent events - like the revelations about president Bush's secret (and highly illegal) domestic spying and wire-tapping program - give the impression that life is imitating art, but adds that in the grand sweep of history he believes these kind of things are somewhat cyclical and repetitive. "I mean the original graphic novel was written in the '80s, on the back of the Thatcher-ite period, and they had some of those same things, like the population being watched and listened in to. Then, when we got about doing the adaptation of the graphic novel, I don't think you'd have to be Nostradamus to see the things that were going on around you. Hence we had stuff about wire-tapping, avian flu and sedition - that was just a reaction to us being aware of what was happening. I thought it would be good if the film could speak to the past, but be rooted in the present and also look to the future as well."

Despite having his face hidden from view for the entire film (the one time he forgoes the Guy Fawkes mask, V replaces it with a different visage), Weaving brings the complex character of V to life with his mastery of technique, delivering a richly detailed performance that completely transcends the limitations of his costume and make-up. McTeige says he also decided, early in the piece, to capture Weaving's performance in real time, alongside his co-stars as they interact together. "I guess there had always been the temptation to just say: 'okay, we're gonna record your voice later, so we'll only do this once and then we'll move on', but what I really wanted to do was get to the emotional heart of the scene, and he knew very intuitively how the mask would work and how he would be able to use his physicality, and use his voice, to be very nuanced with it. I used the lighting and did a bit of stuff on the mask in post production, so I think it was a sort of great team effort to make that character believable, but in the end Hugo owns the role because he is a great actor."

There's no great 'reveal' moment, either, adds the director, because "It would have made him just a man, and taken away from, in a certain regard, what the film's about: you know, the power of the idea being greater than the man. What you want to do is humanise the character, but at some point he has to become the idea, so the idea carries on; and that's the great part of working with the mask: you don't get physically attached to the person, but hopefully you get intellectually attached to the idea of what that mask represents."

In the course of her journey of discovery, Evie is imprisoned and has her head shaved bare before being interrogated and abused. McTeigue says that Natalie Portman barely flinched at the idea, all the same. "She was great about it actually. She's a very brave, intelligent and amazing young actress - probably the actress of her generation, I believe. We actually only had one conversation about shaving all her hair off, and I think she saw it as an opportunity to let some of her vanity go and for it to be liberating. I upped the ante by doing it onscreen - of course you don't get to go back and re-do the shot, but we put little fail-safes in there: you shave a couple of heads immediately before you shave her head; you run a lot of cameras on it - you know, turn 'em all on and hope for the best. I got her hairdresser to be the one to do the shaving as well."

Working with such a strong supporting cast as well, says the young Australian, was a luxury that could only have come about with the combined clout of the Wachowski brothers and producer Joel Silver. "A lot of those actors, like Stephen Rea and Sinead Cusack, were like first choices for me. I got lucky, but that's what happens when you have the Wachowskis and Silver in your corner: people become interested in the film you're making because they know that you're probably going to be making an interesting film. They read the script and they get excited, and they trust you - that's what actors do: the trust you to guide them to a good performance - not that they haven't already got it in them anyway - but with those people, whose reputation is so large and imposing, when you get to meet them as people that's just not in the equation any more I guess.

"That doesn't mean I didn't get a little bit nervous at times," McTeigue adds with a laugh. "The first time you walk up to John Hurt to give him a bit of direction, you know, you tend to think pretty carefully about what you're going to say. With that Chancellor Suttler character, I got him to probably play it a little bigger than he wanted to play it, but he was brave enough to go there and let me do it, let me push it to the limit and then decide, in the editing room, what worked and what didn't work. I think one of the great things that he said to me, like the first time he saw the film, was at the Berlin Film Festival: we walked out, as the credits were rolling, and off to the side there was a stage before we got introduced when I walked up to him and I went: 'fantastic performance there, sir', and he said: 'I can't believe they let you fucking make that film' - which was kind of cool."