(I'll do my best to avoid spoilers, but I'm going to be talking about the differences between the comic and the film, so if you haven't seen it, I'd avoid this entry for now)

Firstly, we shouldn't be under any illusions. V For Vendetta, the comic, is not a flawless masterpiece. As one of Alan Moore's early works, it is hamstrung by the structural constraints placed on its serial in Warrior, coupled with the final book being written several years after the first two (because of Warrior's demise). Even the setting of the original story is a little suspect, a failing Moore acknowledged in the introduction to the graphic novel edition and during interviews around the same time - "We had supposed that it would take a nuclear war to make England veer towards fascism. In the end all it took was giving people the right to buy their own council house." Despite all this, it's still a powerful polemic, as subtle as a bag of hammers in places, and as subtle as a scalpel in others.

Ever since the film was announced, fans of the book have been worrying about it, especially since early rumours indicated that the film would be set in "an alternate reality where Germany won World War II," which would have rather undermined the whole point of the story. Oh, and then there was V's introductory speech, which consisted of him saying a lot of words that began with the letter V.

The bad news is that the speech is still in there, although thankfully, it doesn't crop up again. The good news is that the WWII rumour was just that, and in fact, the Wachowski brothers have updated the story to reflect today rather than 1982. Instead of a nuclear war, we have a bioterror event that leads a Conservative MP to form a new party, Norsefire, which eventually wins Parliament (the book implies the slight collusion of the Royal Family; the film gives the new leader the dubious title of High Chancellor, suggesting that the WWII rumour may have come from an early draft of the screenplay).

Moore and Lloyd's version is very working class, capturing the grimy nature of Britain in the early 1980s. By contrast, the film is middle-class; instead of back-breaking and poorly-paid work at a munitions factory, Evey is a seemingly well-paid PA at the British Television Network. Some have said that this weakens V's point, as most of the characters seem to have reasonable lives, but I don't think it does. After all, if you weren't a Jew, you could get on quite well in 1930s Germany, and you could turn a blind eye to some of the measures that were going on around you. As they did.

Some of the changes don't work - I felt that V's television broadcast was pointlessly altered from Moore's more intelligent version, and I was sad that the lack of CCTV camera meant we didn't get the little girl's "bollocks!" scene in all its glory (it's partly in there, but it's not quite the same). Also, the removal of Fate means that the film has a few extra plot holes (how did V manage to send all the parcels? How did he set the trip in the police file for Finch to find?). Finally, the Shadow Gallery seemed a little pointless - as the censorship of Britain was much less restrictive than in the original (and while I love that Cat Power track, it didn't have the same resonance as "perhaps the term Tamla Motown" is familiar to you? Obviously not. Hardly surprising, I suppose. After all, they eradicated some cultures more thoroughly than they did others.")

No punches are pulled in the torture scenes; if anything, they're worse than the comic, borrowing images and devices from Abu Ghraib and Guantanamo Bay. Valerie's letter is also handled better than I thought it would be, and the change in Gordon's character, played by a film-stealing Stephen Fry, results in a much stronger connection between Evey and him, at the expense of some of the father issues explored in the book.

The finale has come in for quite a lot of criticism, and I have to confess that the touch of magic realism at the end didn't quite work for me, and I yelled at the screen (for which I apologise) for the American-centric suggestion that the Army can be relied upon to have honour (having watched The Plot Against Wilson this week, it's obvious that we can't. And if he hadn't been killed by the INLA, I would imagine that Lord Mountbatten would have played a large role in the original comic). I'm willing to forgive them a bit, though, as producing a blockbuster film that has that ending in today's climate takes some courage.

So, did I like it? Well, I feel a little compromised by knowing the book. The trailer promises an action-packed film, and this really isn't (much to the consternation of some in the theatre). At the same time, some of Moore's ideas about Anarchy have been watered down or removed to make the film simpler - at one point a supermarket is held up by a robber shouting "Anarchy in The UK!", which is followed by a Cabinet briefing on "the chaos", sidestepping V's explanation in the book of the difference. Having said that, it's still a very interesting message for 2006: "Governments should be afraid of the people."