The Dark Knight

Is everything falling apart or is it just us? It's been a traumatic start to the new century and then late in the decade comes a supposed Hollywood comic book blockbuster that asks: do we deserve to be saved from the terrorists? Or has democracy failed, and would we be safer under a fascist regime led by a man dressed as a bat?

Christopher Nolan's The Dark Knight is an annihilating experience, especially if you watch it in the enormous IMAX theatre, a vertiginous phenomenon at the best of times; when that eight storey screen fills up with the scarred, sweating, greasepaint-smeared face of Heath Ledger's Joker, speaking of chaos and the cannibalism lurking under civilisation, the temptation is to run screaming into the night. The action is devastating, high-wire and realistic. The ideas are even more destructive, presenting Western civilisation as a precarious condition liable to break down when threatened with an enemy it cannot bargain with or buy off, an enemy who is insane and only wants to see it burn.

That's hyperbole, sure. But hyperbole is the great stage upon which the modern mythology of comic book heroes plays out. The screenplay written by Jonathan and Christopher Nolan, with additions to the story from David S Goyer, synthesizes crucial elements from two of the greatest Batman comics, Frank Miller's 'The Dark Knight Returns' and Alan Moore's 'The Killing Joke'.

From Miller's groundbreaking portrait of an ageing Batman, the screenplay inherits the malign influence of a masked vigilante upon society, and what demons are unleashed as an unintended consequence of the thrilling psychic and social disorder inspired by a Batman. From 'The Killing Joke' it extracts Moore's Joker, a connoisseur of insanity, visiting the same madness that led to his creation upon our heroes.

The screenwriters have added a third provocation: when the Roman Empire had the barbarians at the gate, they suspended democracy and handed rule over to one man, Caesar, to protect them. Could Batman be the new Caesar? The Dark Knight puts us through the wringer on this one, toying with fascism as a way out of the endless fear and crime before showing, at its close, that even the best of men would be corrupted by the responsibility of being judge, jury and executioner.

Christopher Nolan's first pass at this material was Batman Begins in 2005, a dark and gloomy movie, no doubt, but it needed a dose of the Scarecrow's psychedelic poison to set the citizens of Gotham at one another's throats.

This time, Heath Ledger's Joker drips fear and disorder into the body politic and the results are far more disturbing. Ledger tragically died after filming was completed, and the premature death of such a coruscating talent contributes a terrible urgency to his performance, rubbing away at your knowledge that the actor was just messing around. With his lank unwashed green hair, hunched shoulders and restless tongue, always drawing back the saliva from the scars at the corner of his smile, this Joker is all our fears of the amoral urban dispossessed (he likes his knife crime) multiplied by our terror of the suicide bomber, the killer who cannot be reasoned with, the murderer who wants nothing but our destruction. He is Kurt Cobain's self-hatred directed outwards, a nihilist to make Nietzsche quiver.

Against the forces of darkness, we have a white knight. Aaron Eckhart's district attorney Harvey Dent, who wages effective war against the upper echelons of Gotham's criminal classes. Together with Gary Oldman's Lieutenant Gordon and Christian Bale's Batman, the forces of law and order gain the upper hand. Rachel Dawes, played by Maggie Gyllenhaal, falls in love with Dent, an unexpected twist in affairs as Batman Begins had Rachel - then played by Katie Holmes - all set up to be the love of Bruce Wayne's life. Harvey and Batman's campaign is so effective that the criminals are forced to turn to the Joker, and so both men are responsible - if not entirely culpable - for the horrors that are unleashed, on the city and on themselves.

The Dark Knight succeeds where other comic book movies fail because of its bone-crunching physicality. On the IMAX screens, even the establishing shots of swooping city vistas are a white-knuckle ride.

When the filmmakers flip a 40-foot tractor trailer in the heart of Chicago, you'll never want to see another computer-generated fight sequence again. That physicality also comes from the actors. Christian Bale thinned himself right down for The Machinist and was a raw-boned prisoner of war in Werner Herzog's Rescue Dawn; his martial arts work as Batman makes the close combat sing.

Heath Ledger's Joker is like the wolf in 'Little Red Riding Hood', a mangy and disguised beast with a sardonic wit. He achieves more with one nurse's outfit than Jack Nicholson managed in the entirety of Tim Burton's Batman. It's only when the second villain of the piece appears, the horrific Two-Face, that we get a glimmer of computerised special effects - the result, by the way, is so bleak and scary that parents are advised against sneaking their little ones into this movie unless they want them to grow up disturbed.

The supporting cast add vital colour and context. Michael Caine's Alfred has the wisdom of a battle veteran, and his anecdotes from his time in Burma situate the comic book battle in the actual history of war. Morgan Freeman's Lucius Fox once again plays Q to Batman's Bond, and provides an ethical check to the hero's flirtation with Big-Brother-style fascism. Gary Oldman's Lieutenant Gordon is the pragmatic face of the good cop who teeters on the edge when his family is threatened.

The coup de grace of The Dark Knight is its structure. An ending seems to come, and emotionally you are drained but prepared for a third film that will complete the trilogy. That third film then unfolds before you. Here the gates of hell open up with the appearance of Two-Face and the further ramifications of the Joker's plan.

Too often superhero films climax with a dull slugfest between computer-generated heroes and villains: here the ending reminds one of Fight Club's tower block-set face-off with something of Sophie's Choice and Michael Mann's Manhunter ; an emotionally draining encounter that ensures the film does not disappear into a flurry of special effects.