The Big Picture: Black Hawk Down (15)

As an orchestrator of roiling chaos, Ridley Scott has no obvious peer at the moment. Having ushered us inside the tumultuous, you-are-there frenzy of the Colosseum in Gladiator, he sets about creating an even more ambitious facsimile of combat in Black Hawk Down – ambitious because his milieu is no longer a confined space but a whole city, whose every street and rooftop bristles with deadly hostility. This film presents battle as an open-air slaughterhouse, and documents the traumas of a long firefight with the kind of unrelenting energy and visceral close-ups that made the first 25 minutes of Saving Private Ryan so memorable.

The films share a theme, too – the valour of self-sacrifice in war – though Black Hawk Down mostly avoids the rhetoric of Ryan. That's just as well, because the enemy here isn't Nazism, but a savage street army whose ideological purpose, if it has one at all, remains obscure.

The film is adapted by Ken Nolan from Mark Bowden's best-selling book about an ill-starred Special Forces operation in Somalia in October 1993; what ought to have been a swift "extraction" turned into a débâcle in which 18 Americans were killed and many more injured. An on-screen prologue explains that a combination of famine and civil war had persuaded the United Nations to send a peace-keeping force into Somalia. Doubtful of its effectiveness, Washington decided that a more hands-on approach was required. In order to neutralise the threat of the chief Somalian warlord, Mohamed Farah Aidid, the US military plans to kidnap several of his lieutenants from their base of operations in downtown Mogadishu.

As zero hour approaches, we are introduced in short order to key members of the task force, divided between young shaven-headed Rangers (including Josh Hartnett as a soft-spoken idealist, Ewan McGregor as a desk jockey who's never seen combat, and Orlando Bloom as a superkeen rookie) and the veteran Delta Force soldiers whose M O is based on hard-bitten pragmatism. Scott has recruited quite a team here – Tom Sizemore, Jason Isaacs, Ewen Bremner and Jeremy Piven are among the distinctive faces – and part of the suspense lies in trying to guess who's going to make it back and whose number is up (poor old Ioan Gruffudd doesn't even make the squad, struck down by an epileptic fit at base camp, forcing Hartnett to take the sergeant's pips).

But the film doesn't dawdle over these preliminaries; one senses Scott itching to get this mission off the ground and to show us what he can do with his camera – the needle-sharp cinematography is by Slawomir Idziak – most noticeably in the sinister beauty of the Black Hawk helicopters silhouetted in formation against a pearly sky. (Though their compact size makes them look oddly vulnerable – these aren't the thumping helicopter gunships of the Vietnam years.)

Almost immediately the mission starts to go wrong, and the film's pace breaks from a steady canter into a panicked gallop. Tending to a Ranger stricken by a 60-foot fall from a helicopter rope, Hartnett and co are fatally delayed; a Black Hawk is shot down, then another, and before long crowds of Aidid's men, armed to the teeth, are closing in on the crash site.

This is the point on which the story turns: rather than bolt from this "hornet's nest" and save themselves, the soldiers stay put to recover the crash survivors, a principle sacred to the Rangers being never to leave a fallen comrade in the hands of the enemy (it gives the film its tagline: "Leave No Man Behind").

Trapped within the city's labyrinthine streets and under heavy fire, the Americans try to regroup, and suddenly base command has a rescue mission on its hands. As the Maj General in charge (a laconic Sam Shepard) puts it: "If we don't hold back this city, we're gonna have a hundred caskets to fill by tomorrow morning."

The number of enemy casualties isn't certain, but it's plain to see that the Somalis – "skinnies", as the Americans call them – suffer terrible losses. An epilogue puts the figure at over a thousand. Did the US military help the starving of Somalia by their intervention, or did they merely lop some heads from the Hydra of civil war? The film doesn't say, though the fact that President Clinton pulled the Special Forces out of Somalia shortly afterwards suggests the level of success. Nor are the geopolitical implications of the story pursued; conflict, as the unit's chief dog-of-war Gibson (Eric Bana) observes, isn't about strategy: "It's about the men next to you – that's all it is."

Scott, too, shuns any close analysis of why it happened; his interest lies in what the experience feels like at a gut level – literally, in the case of unfortunate soldiers pierced by shrapnel and spouting dark plumes of blood from their stomach. Like Saving Private Ryan and, more recently, Three Kings, Scott does a disquietingly good job of recreating the sound and fury of battle, both in its larger confusions and the minutiae of its ordnance – the way, for instance, spent shells cascade out of an automatic rifle like a jackpot from a slot machine, and stay scalding to the touch.

The violence of Black Hawk Down sometimes tips over from exciting into excruciating, and may cause you a little jumpiness after the lights go up. (On hearing a door slam I executed a swift commando-roll across the cinema foyer.) Yet the restrained matter-of-factness of its presentation is creditable, and there's less flag-waving here than you might think. While Scott honours the nobility and fortitude of the American forces in Mogadishu, he does spare a thought for the innocents caught in the crossfire, their home turned into a battle zone. One suspects it didn't look all that great beforehand; now it's a contender for the worst place on earth. Scott makes us feel for these beleaguered young men, smudged with exhaustion and lacerated from combat. But at least they didn't have to go back there.