The soldiers' story

Four years later, an ugly, foot-long scar, herring-boned with stitches, still slashes his thigh. No longer fit for service, he has started a new career as an actor. Last summer, he returned to the Middle East to play a marine in Nick Broomfield's docudrama, Battle for Haditha, alongside a squad of other former leathernecks also getting back into battledress.

What happened in Haditha on 19 November, 2005 has become, after the events in Abu Ghraib prison, the most controversial single incident of the war.

A marine patrol from Kilo Company was hit by a roadside explosive device just outside the town which lies near the Jordanian border. An officer was killed, and the remainder of the squad exacted a brutal revenge on the occupants of a passing taxi. They then targeted the inhabitants of some nearby houses from which they claimed to have come under fire. Within a few minutes of the bomb going off, 24 Iraqis, including a number of women and children, had been killed.

"The things we depict are all absolutely factually accurate," insists Broomfield. My first impression of him is of a chaotic but good-natured puppy, but the director is clearly all terrier when it comes to getting his way.

It took Broomfield a relatively long time to get into film-making, going first from one university course in law to another in political science, then finally on to the National Film School, where he met his wife, Joan Churchill, a cinematography student who has shot a number of his films. Broomfield's signature of injecting himself into the films he makes - something he was doing long before Michael Moore barged into frame - evolved slowly, but he has always zoomed in on controversy.

His first film, made while still at college, was about slum clearances in Liverpool. His love for the outrageous - and sometimes the openly dangerous - has prompted documentaries about Hollywood madam Heidi Fleiss, serial killer Aileen Wuornos, the Chicken Ranch brothel in Nevada and Kurt Cobain. He also pursued Maggie Thatcher on a New York book tour in Tracking Down Maggie (1994) - which made a virtue out of its director's total failure to get an interview with his subject.

But the Iraq War incident, Broomfield realised, could not be treated as a documentary. "None of the marines I met from Kilo Company who were there that day would be filmed. None of the insurgents whom I met in Oman who came over from Haditha wanted to be filmed either. None of the survivors wanted to be filmed. I think what we've done is a better way of telling this story."

The filming was done in Jordan, as entering Iraq itself was impossible.

Broomfield had access to a 6,000-page report by the Criminal Investigation Service of the US Navy. But what gives the film its authenticity is that the screenplay-was developed with a number of former marines and Iraqis - which is how Elliot Ruiz became involved.

"Nick just let us be us," he says. "I was really worried that the film would misrepresent the US Marine Corps," says Ruiz, a cheerful, friendly man whose demeanour suggests there is a tightly coiled spring somewhere inside.

"That was my only hesitation. I told the friends I served with that I was going to do it. To be honest, their opinions are the only ones that really matter to me. The only other reaction we've had has been the blogs, and that's just a bunch of people who don't really know what is going on. I'm pretty sure that, when they see it, their opinions will change."

"The film is fair," insists the director. "More than anything, I wanted to understand what had happened and what had gone through the minds of the people on that day. It's one thing to say George Bush's policy of putting them there is completely misguided. It's quite another thing to lock up a whole lot of guys who joined the marines at 17 and did things which, agreed, are terrible to have done, but they did them in a situation so inherently terrible that it makes it almost impossible to judge them."

Broomfield depicts the marines as professionals who respond to the situation in the way they have been taught.

"They're trained to react with overwhelming force," Broomfield points out. "They're much more aggressively trained than our troops. And they've seen their colleague killed: the particular guy who died was very popular."

Ruiz's fellow marine, Eric Mehalacopoulos, who served two tours in Iraq, plays a marine sergeant in the film. He reckons the Kilo Company portrayed reacts the way he would have done.

"The reason the film is so genuine is that we relived our experiences and put it on film," he says. "The Marine Corps is a profession. You're trained to kill - but you're trained to use judgment."

The only judgment exercised by the US military after the incident was to look for the best way of covering it up. The local marine commander, claiming he was not "unduly concerned" by anything that had happened in Haditha, put out a bland press release talking about a number of insurgents being killed. Broomfield who has a talent for understatement describes this document as " completely bonkers", and points out that none of the 24 Iraqi dead was on the US database of insurgents.

The incident would have remained buried if a video shot by an Iraqi student showing the bodies lying where they had been found had not reached Time magazine, which investigated in depth in 2006, eventually forcing the US military to take action. The members of Kilo Company are currently on trial for murder at Camp Pendleton in California. No officer is among the accused.

This enrages Mehalacopoulos. "That's always the way it happens," he says. "It's the little guy that pays. There's a lot of politics in the military. There are people taking orders and doing the dirty work while somebody higher up skates on by. It shouldn't be like that."

Broomfield's film was backed by Channel 4, who will broadcast it as part of a season marking the fifth anniversary of the invasion of Iraq.

But the director is less than happy about the way British TV treats documentaries these days. "I agree with what Jeremy Paxman said at the MacTaggart Lecture in Edinburgh - we've become ratings mad. That's the only value by which broadcasters judge themselves. The whole public service function, which initially the BBC was set up to achieve, has been forgotten.

"Even the news is judged by ratings, not by the fact that, in a democracy, we need the information to function properly and hold the government accountable. This is a new form of political censorship."

Battle for Haditha will be released in cinemas on 1 February. It will be shown on Channel 4 on 17 March.