It was the first cinema adaptation of Vanity Fair in nearly seventy years. Reese Witherspoon is the token American among Brits as Becky Sharp, but much more interesting for me was the name of the director: Mira Nair. Salaam Bombay, Monsoon Wedding... this is not someone I'd have expected to see taking on a 19th century English classic, but I suppose in 1995 one could have said the same for Ang Lee.

Is it an Indian movie? No. They filmed in Rajasthan for the scenes of Jos and Dobbin in India, which adds a surprising amount of colour and character to the film, but for the most part we're looking at a British costume drama starring Brits in Britain. There's a lot I liked here, with some memorable performances and a story that efficiently condenses Thackeray's gazillion pages into 140-odd minutes without feeling rushed. I found it rather refreshing, actually. It's interesting to see how well the story manages without some of the book's set-pieces, such as Jos getting drunk at Vauxhall Gardens. The only parts that really feel perfunctory are Mr Sedley's bankruptcy and the build-up to Waterloo, while a generous soul might perhaps argue that the latter is also suffering from the fact that films can't shift genre as easily as a sprawling novel or TV series. It's also possible that Mira Nair doesn't have a clue about war movies, but what the hell. It's forgiveable, anyway.

I'm not including the Dobbin-Amelia finale in that analysis, mind you. The film's entire climax goes so spectacularly off the rails that it doesn't seem particularly useful to judge it along with the rest of it. Most of this film is an interesting and very watchable adaptation of Vanity Fair, but it's trying to rewrite the plot in one respect so goofy that in the end it kills the entire story.

Only Hollywood could have come up with this. Reese Witherspoon's Becky Sharp is a good person. No one would ever watch a movie with an unlikeable protagonist, right? They're trying to give their version of Vanity Fair a traditional heroine, which strikes me as akin to turning The Texas Chainsaw Massacre into a romantic comedy. This film's Becky isn't merely doing bad things with charm and wit, but instead never doing anything bad at all. She's a put-upon saint. Hardships and humiliations are visited upon her, which she endures with spirit and gumption. It would seem that she loves her son as a mother should, innocent people never suffer because of her actions and she never shows any character trait more negative than cheekiness.

Does it need saying that this sucks? Admittedly it works better than you'd think for most of the film, which would be the "interesting and very watchable" bit I mentioned earlier. Apart from the occasional eye-rolling moment, this anti-Becky can follow in Thackeray's footsteps without actually doing violence to the story. Reese Witherspoon is fine, to the extent that I'd have quite liked to see her in a less wrong-headed adaptation, and there's plenty of colour in all the characters around her. However once we've hit the second half of Thackeray's novel, it becomes clear that by stopping Becky from doing evil horrible things to the people around her, they're basically preventing her from doing anything at all. She's passive! Terrible things happen to her and she lets herself be a victim! There's a car crash fascination in watching all this, I suppose, but to be honest its chief value lies in being a lesson for future generations. "Look, it doesn't work. They tried it in 2004."

The bigger groaner for me was Becky selling her horses at Waterloo not for money, but for a seat in a carriage which she then gives up for the sake of Amelia. That made me want to throw things at the scriptwriters, but on the upside it didn't derail the story. The film as a whole doesn't crash and burn until we reach the finale, in which Becky's downfall comes across as nothing more than the script randomly being cruel to a heroine who's done nothing to deserve it. After that Thackeray's plot dictates that she live forsaken and in poverty for many years, never approaching her friend Amelia for help until they run into each other randomly on the Continent and even then Dobbin seems to think she's the devil in disguise. In the novel, he was right. However the film can barely bring itself to find anything bad for Dobbin to say about Becky, which turns him into a shit who's clearly in the wrong in his climactic argument with Amelia. The novel's one truly great passage becomes perfunctory Hollywood bollocks, with Dobbin's renunciation having been given not an ounce of set-up and as a result is coming across as false jeopardy.

Oh, and Lord Steyne falls in love with Becky. No, really. I laughed at the screen.

You don't have to be a literature geek to cry bullshit at this. The reason it's so bad isn't that it's unfaithful to the text. On the contrary, the finale would have been improved by throwing Thackeray in the bin and instead having Peter Pan carry Becky away to Neverland or something. What's funniest isn't that Becky snaring Jos at the end is a happy ending, since that was always going to be inevitable. No, suddenly the worry is that our heroine deserves better than merely ensnaring a fat old git, so the film's final sequence is of Jos showing Becky the wonders of India. It looks amazing, I'll give it that.

The casting interests me, because I'd been expecting a Hollywood movie to get better actors than a TV series. They don't. They're comparable, but this cast strikes me as being a worse fit for their roles. Insisting on bankable box office names will restrict your casting choices, while it's also noticeable that the young leads seem to be younger, more handsome and sometimes less talented than you'd get with the BBC. It's not even as if both productions weren't casting from the same pool of British character actors, as is demonstrated by the BBC's 1998 Becky (Natasha Little) getting a part here as Lady Jane Sheepshanks. I didn't mind Reese Witherspoon, but she's not even the best Becky Sharp in this film.

However to pick out people I liked, this film probably has my favourite Rawdon and Miss Crawley to date, in the forms of James Purefoy and Eileen Atkins. I don't know if I'll ever see the Miss Crawley who lives in my head, but Atkins comes close. I was also intrigued by Gabriel Byrne's Lord Steyne, who's starting to strike me as the chameleon of Vanity Fair. Everyone else is clearly defined, but Steyne can become whatever kind of evil you want him to be.

Of the others, Rhys Ifans's Dobbin is better than the script's making him look. I'd say the same of Tony Maudsley's Jos, except that he's so under-represented that it's almost impossible to tell. Romola Garai's Amelia is uninteresting, but we'll be generous and call this an acting choice. I was happy to recognise John Woodvine as Lord Bareacres, but he's hardly Graham Crowden. None of these are particularly memorable, but they're all in rough accordance with what you'd expect. That's not even remotely true of the two big names I haven't discussed yet: Bob Hoskins and Jim Broadbent. I like them both, but they're cuddly, lovable teddy bears who struck me as almost wilfully counter-intuitive casting for their spiky, unpleasant roles. Was Mira Nair deliberately trying to avoid comparisons with the 1998 series?

I like the slovenly, energetic charm of Hoskins's Sir Pitt, but you'd never call him sleazy. Jim Broadbent though is so wrong but brilliant that it's almost hypnotic. I think he's doing a counter-reading of the normally dark and intense role of Mr Osborne, to the extent that I wasn't always even convinced by his choices, but he's such a wonderful actor that he makes it work anyway.

All but one of the cast I thought were somewhere between passable and fascinating. The exception is Jonathan Rhys Meyers, who struck me as the kind of talentless pretty teenager who'd be lucky to be carrying the tea on a BBC adaptation. He's downright awful as George Osborne, being such a bastard that Dobbin would have to be a gibbering idiot for wanting to help him marry Amelia. "He'd have jilted you but for Dobbin," says Becky at the end. Actually that wasn't what we saw at all, which I remembered distinctly because at no point had I retrieved my jaw from the carpet. Anyway, you wouldn't put money on that marriage lasting a week, yet for one scene George appears to grow a sense of morality as he defies his (cuddly) father and throws away a fortune. Admittedly they've cut back so much of the original story that Meyers was always going to be trying to square a circle, but it's a challenge he doesn't even threaten to meet.

Despite everything I've said, there are quite a few things here worth watching for. Its pace occasionally backfires, but overall I found it refreshing. I was surprised by Amelia's mother, whom they've made downright venomous. They have an interesting take on the racial side of things, with Miss Swartz in particular being given a point of view I'd never seen expressed before. It seems more in sympathy with the feminine point of view than I personally get from Thackeray, with a brief discussion of giving birth between Becky and Amelia and an eye-gouging shot of partial nudity that you wouldn't have got from a male director. I was also entertained by its Indianness, with singing and at one point even a Bollywood dance number.

This film is 20% great, 70% good and 10% travesty. Unfortunately its problem is that most of the worst comes at the end, which is what kills the film. If only they'd been able to hide that 10% somewhere in the first hour and keep back some greatness for the finale, we'd have been calling this as a masterpiece and it would have done far better than being nominated for a Golden Lion at the 2004 Venice Film Festival. I enjoyed a lot of this and I'm glad I watched it, but by the 2-hour mark I was actively pissed off. By all means watch it, but be warned.