Hollywood stars Tim Blake Nelson and Harvey Keitel have made a controversial Holocaust movie about the Jews who survived the camps by helping the Nazis commit genocide.

The Grey Zone is one of the most fascinating Holocaust films ever made, yet it never reached UK cinemas following its American debut in 2002. While it was released in Israel, Germany and Spain, among other markets, UK distributors baulked at the movie’s unredemptive narrative and stark, despairing tone. This week, it is finally released here on DVD.

Written and directed by the Oklahoma-born actor Tim Blake Nelson, The Grey Zone is based partly on Primo Levi’s essay of the same name and the eyewitness account of Miklos Nyiszli, a Hungarian Jew who avoided death by working as Josef Mengele’s personal research pathologist. It compellingly investigates the impossible moral choices facing prisoners forced into the Sonderkommando.

These special squads were charged with running the camps’ crematoria. They maintained order among the new arrivals — or “cargo” — on their way to the gas chamber, removed the corpses, pulled gold teeth, cut women’s hair, and sorted and classified clothes, shoes and other belongings. They oversaw the burning of the bodies, and the collection and disposal of the ashes.

In exchange, they received larger quarters, books, better food, alcohol, cigarettes and the right to loot the dead. After four months, they were slaughtered themselves.

The Grey Zone focuses on the 12th Sonderkommando of Auschwitz II- Birkenau, who, in their final days in 1944, mounted an armed rebellion. None of the squad survived, but they destroyed half of the crematoria, which were never rebuilt, and killed 70 SS soldiers.

“I wanted to explore how the concrete story of the 12th Sonderkommando created moral abstractions which are ultimately impossible to comprehend, but which at least can be experienced by an audience member,” says Nelson, now 44, who adapted The Grey Zone from his own award-winning off-Broadway play.

“As an able-bodied Jew in my thirties, I could see myself in the very situation the Sonderkommandos faced. The film is an attempt to explore that predicament: would you save yourself, essentially by abetting the slaughter of others? Or would you, as most of us would like to think we would, refuse to do the work and be killed?”

The Sonderkommando are one of the most controversial and sensitive issues in Jewish history; they illustrated Levi’s point that life in the camps could not be “reduced to the two blocs of victims and persecutors”.

“I grew up hearing that Jews were innocent victims, Nazis were evil perpetrators, and there was no area in between,” says Nelson. “This, to me, is no way to look at history.”

Harvey Keitel, one of the film’s stars and executive producers, admits that not all the survivors who read Nelson’s script approved. “Some felt we should not make the film, that we had no right to do so; others felt we should. I had to agree with both; that we had no right, and that we had to.”

The filmmaker Joel Coen, who had directed Nelson in the comedy O Brother, Where Art Thou?, urged his friend Nelson not to do the film. “Joel is quite keenly suspicious of any Holocaust movie,” says Nelson. “He’s of the mind that it’s next to impossible to make a film about this that works.”

Avi Lerner, the film’s veteran producer, on the other hand, believes The Grey Zone needed to be made. Raised in Haifa, he recalls an old couple who were Holocaust survivors living in his building. As a child, he was fascinated by the numbers on their hands, but they never talked about the past. “Later, I felt that they felt guilty for surviving,” he says. “And this is the question I ask myself even today: ‘What would I have done in their situation?’”

Very few Jews retaliated, he says. “As I grew up, that brought me to the fact of why Israel is so important. I went up through the Israeli army and became a paratrooper and an officer, because it was a matter of surviving.”

All of this informed his decision to fund The Grey Zone, even though Lerner knew it made little commercial sense. “I just felt it is a part of my life, it’s a part of any Jewish person who’s growing up in today’s world and asking himself why they didn’t resist, why they helped the Nazis, why they were living like this.”

Nelson’s quest for authenticity took The Grey Zone further than any other film in terms of its evocation of the mechanics of the Holocaust. Undeterred by Shoah-director Claude Lanzmann’s belief that the Holocaust is beyond the grasp of narrative film, or even filmic representation — “There is a certain degree of horror that cannot be transmitted. To claim it is possible to do so is to be guilty of the most serious transgression,” Lanzmann has said — Nelson recreated Auschwitz’s crematoria in Bulgaria, taking the viewer through the entire process of reducing humans from flesh-and-bone to ash. “If what you want to do, as an artist, is to illuminate the human condition in any small way, then it seems to me that tragic historical events like the Holocaust are exactly what should be dealt with in artistic media such as film,” argues Nelson. However, he would not have made a film set during the Holocaust at all if he felt it had nothing to say about our lives now.

Indeed, before writing his play of The Grey Zone, he had worked for over 18 months researching and writing a play about his grandparents’ (his grandfather was a lawyer disbarred by the Nuremberg Laws) and mother’s experience in Weimar Germany and during the rise of National Socialism, and finally their escape on the eve of Kristallnacht. But “because it felt so familiar, I cast it aside”, he says. “I don’t think people have the time, interest or energy to experience Holocaust stories that are redundant at this time.”

The Sonderkommando’s story seemed relevant to him because of how chillingly desensitised the men became: “How workaday, even for the Jews, the violence was. What they learnt was to ignore,” says Nelson.

After the Abu Ghraib scandal in 2004, and other recent atrocities, The Grey Zone seems more relevant than ever.

“I believe, in the hope of not permitting this to ever happen again, that it is best to look at the slaughter of the millions of Jews and gypsies in the concentration camps, and take a close look at the Jewish people who were there,” says Keitel. “It seems to me we must come to terms with the ability of humankind to slaughter children, to slaughter women, to slaughter helpless people. We have the capacity to do that. But we also have the capacity to pick up a gun and kill back to stop the slaughter.”

The Grey Zone is released on DVD by DNC Entertainment Ltd