Dir: Paul Greengrass. 2002. UK/Ireland. 107 mins

The end of this month marks the precise thirtieth anniversary of Bloody Sunday, the name given to that sickening, catalytic chapter in Anglo-Irish history in which 14 unarmed civilians were slaughtered by trigger-happy British paratroopers who had been ostensibly brought in to control a peace march through the city of Derry, Northern Ireland. Adopting an unwavering pseudo-documentary style that vividly re-enacts the mayhem of that ugly day, as experienced from both sides of the rifle cross-hairs, Paul Greengrass' tightly focused film uncoils with all the awful inevitability of a Shakespearean tragedy - albeit of a stripped-down and grungy variety. Despite being made primarily for British and presumably Irish television, this is a work of such intensity and commitment it cannot fail to resonate among news-literate types elsewhere in a world wrestling more and more with the root causes of political violence and partisan bigotry as perpetrated by condemned terrorists, self-anointed freedom fighters or even sanctioned governments. Realistic almost to a fault, Bloody Sunday's commercial prospects will be hamstrung by the thick Ulster accents and a resolute refusal to instantly explain jargon terms such as 'pigs', 'provos', 'paras' and the 'RUC' that are all but meaningless outside the British Isles. Nonetheless, the evident injustices of that will continue to fire up even the most uninitiated of international festival audiences as it has already done at Sundance and stir up necessary media debate wherever it secures specialised distribution. At press-time, Paramount Classics was reportedly closing in the North American, Latin American and Japanese rights to Bloody Sunday.

As a filmmaker, Greengrass is perhaps best known beyond the UK for his limited release theatrical feature The Theory Of Flight starring Kenneth Branagh and Helena Bonham-Carter. But it is his experience in directing factual drama, notably The Murder Of Stephen Lawrence that aired this week on US television, and his seminal work as a TV journalist covering the IRA hunger strikers in the Maze Prison, that clearly informs his latest film. Here he dispenses with cinema's usual armoury of lighting and camera tricks that turns battle scenes in such films as Ridley Scott's Black Hawk Down into carefully choreographed sensual spectacles in favour of an unadorned music-free approach to filmmaking that mimics what might have been recorded had a documentary camera crew been present on January 30th, 1972. There are no dolly or overhead tracking shots here; indeed, in some scenes the prowling hand-held camera seems to be anxiously searching for source of the developing drama as it is played out by an impeccable cast among the back alleys of a depressed housing estate of high-rise concrete.

The fact that the handful of professional actors are aided and abetted by hundreds of actual ex-soldiers and memory-scarred Derry residents gives Bloody Sunday an atmosphere of austere authenticity and a palpable sense of tension. Serving to heighten that is Greengrass' shrewd choice to telescope the entire conflict into a classical time frame of a dawn-till-dusk narrative that is punctuated by quick cuts and fades to black. Rather than provide a sweeping perspective as to why Irish communities like Derry have been besieged by 700 years of political and religious tumult, he throws us right into the particularities of this localised event and leaves its socio-historical complexities and watershed implications to become gradually apparent as the hours count down inexorably to the 15 minutes of cold-blooded carnage.

Without undue fanfare, the film opens with two duelling press conferences that ominously set out the embattled positions of those that will come to blows that fateful day. In the one corner is Ivan Cooper (Nesbitt), the idealistic local Member of Parliament who urges his constituents to join him in a non-violent, Martin Luther King-style demonstration against the controversial British policy of arresting undesirables and interning them without trial; in the other are the British armed forces in Northern Ireland, led by their overall commander Major General Robert Ford (Pigott-Smith), who want to do everything in their power to contain these young Derry "hooligans".

This being Ireland, of course, none of the respective battle-lines are so neatly delineated. Cooper, while identified with the Catholic cause, also happens to be Protestant (as is the actor who portrays him), a religion long allied to the pro-British royalist movement. Similarly, Gerry Donaghy (Duddy), the young Catholic hot-head who was to end that day on the list of martyrs, wants nothing more than to settle down and marry his Protestant girlfriend.

Even the British side betrays tensions: there may have been clear orders from the British Government to use maximum aggression in making as many token arrests as possible, but not everyone seems agreed on the means for executing that command. At the onset, Brigadier MacLelland (Farrell) seems only too happy to teach the Derry stone-throwers a hard lesson they'll not forget, but then becomes clearly uncomfortable at having to involve the notoriously heavy-fisted Parachute Regiment as ordered by Ford. Add into this inflammable mix the shadowy presence of IRA trouble-makers, and some kind of violent confrontation seemed unavoidable however idealistic and peaceful Cooper's intentions had been. What no one could have predicted, however, was how quickly water cannons, tear gas and rubber bullets would give way to indiscriminate rounds of live ammunition that would then help fuel a 25-year cycle of sectarian hatred.

For all his steadfast attention to detail, based largely on testimonies gathered in co-producer Don Mullan's book Eyewitness Bloody Sunday, Greengrass loyalties are clearly mapped out from the start. He completely humanises Cooper's character and that of Donaghy in ways that cannot be said of any of the British military figures. And the final harrowing scenes in Altnagelvin Hospital, where the over-stretched staff try to cope with the overwhelming rush of casualties, are unashamedly manipulative, particularly since some of the grieving actors were actual relatives of the deceased. But for the most part, Bloody Sunday remains admirably restrained even to the point of de-mystifying and downplaying what in many Catholic eyes is a massacre of epic proportions - and the effect is all the more powerfully immediate for that.

Although clearly intended as an indictment of the British whose actions were completely exonerated by a whitewashing initial public inquest, apportioning blame seems less important here than an attempt to bring out into the open an atrocity that would have remained completely suppressed but for the lyrics of a U2 stadium anthem and a renewed inquiry by the present British Government.

"How long must we sing this song'" wails U2 frontman Bono as the end credits crawl against a black screen and audiences take angry stock of what they have just witnessed through the eyes of an English filmmaker. Well, the answer is as long as it bloody takes to finally recognise and accept the full extent of the tragedy, rather that bicker in the (British) press about the precise historical accuracies of this dramatised account. The first step towards healing is not retribution but acknowledgement.

Prod co: a Granada Film/Hell's Kitchen production made in association with the UK's Film Council (New Cinema Fund) and the Irish Film Board
Int'l sales: Portman Film
Prod: Mark Redhead
Exec prods: Pippa Cross, Arthur Lappin, Jim Sheridan, Rod Stoneman, Paul Trijbits, Tristan Whalley
Co-prods: Don Mullan, Paul Myler
Scr: Paul Greengrass
DoP: Ivan Strasburg
Ed: Clare Douglas
Prod des: John Paul Kelly
Costume des: Dinah Collin
Mus: Dominic Muldoon
Main cast: James Nesbitt, Tim Pigott-Smith, Nicholas Farrell, Gerard McSorley, Kathy Kiera Clarke, Allan Gildea, Gerad Crossan, Mary Moulds, Carmel McCallion, Declan Duddy