Alfonso Cuarón's ménage-a-trois/road movie Y tu mamá también was the arrowhead of the Mexican new wave, currently startling the world. The mightily talented Cuarón's confident camera work, wit and sensuality make him a director who one is certain will be climbing to bigger heights in the coming decade.

His new film, Children of Men, is an exhilarating vision of the near future. Here he discusses the roots of the fantasy and its applicability to today's troubles.

METRO: What does the title of Children of Men mean?

CUARÓN: P.D. James' book is a Catholic allegory, so Children of Men's title comes from a quote of the Bible. The quote is, eh—I don't remember.

We drifted apart from the book in an early stage. From the book we took the premise of infertility, a premise I understood as a metaphor for the failed sense of hope humanity has. We used themes that are shaping the first decade of the 21st century. And we can't go far without touching on the themes of environment and immigration.

Immigration is a global issue, but the problem of this issue is that it has an ideological tendency. In the recent past, the influx of immigrants were beneficial for the economy. The problem is that politicians need to create issues and causes, and they try to kindle these fears of otherness and the fear of the guys who are going to take your land ...

I have to question the ethics of borders when there is humanity in need. When we start segregating ourselves from what humanity needs ... we lose more and more of the sense of humanity as a whole. Now global warming is coming, and environmental issues are going to create new migrations.

I'm a Mexican. There's been a constant migration between Mexico and the United States. And the anti-immigration laws are getting tougher. The United States is clinging to archaic solutions, instead of trying to find new structures. The same country that praises that tearing apart of the Berlin Wall is building a single wall between the Mexico and the States. It's an expensive and archaic solution, and like all such solutions it will completely backfire.

Historically, a good percentage of these Mexicans try to earn their money and try to go back to their country. What's happening now is that it's tougher to go home, you might as well bring the whole family and stay here. There are a lot of people who want to move, but there are more of them that don't want to move. There is a constant economy of displacement in Mexico.

Mexico has the same issues with Guatemala and Central and South Americas, and in many ways the situation there has been more cruel ... that's what I'm trying to say, it's not a local issue, it's an issue that's affecting the world. As with global warming, there's a state of denial about the whole thing.

METRO: Why England as the site of this negative future in Children of Men, then. Why not Mexico?

CUARÓN: We're using England as a Green Zone, a comfort zone; the characters feel they're lucky to live there, but there's a big percentage of outsiders waiting to get in.

METRO: Speaking of England, the third Harry Potter movie, The Prisoner of Azkaban, is the best one according to J.K. Rowling. How did you do it?

CUARÓN: Guillermo del Toro pushed me to do it. He said, "You need to be clear on this. If you're going to do it, you need to honor and serve the material. If you do that, you'll make the movie great."

METRO: Serve the material!? But your movie had the most personality of any of the series.

CUARÓN: We had a great production designer. And we had Rowling. She has all this geography in her mind. The thing that we wanted to do was something we hadn't seen. We hadn't seen all of Hogwarts except in bits and pieces, and there were feelings you were watching a set. Let's link the spaces, let's allow audiences—even if they don't consciously know it—to experience the geography of the place. They'll know that if there's a corridor, there's going to be a clock, and if you go past the clock, there is going to be a courtyard, and beyond that, a bridge, and then down to the mountain, there is Hagrid's hut. We did something similar in Y tu mamá... and Children. There are very few close-ups. We tried to make Hogwarts a character.

METRO: The guerrilla war scenes in Children of Men had rare shock to them; they're some of the finest I've seen. You didn't sacrifice horror for spectacle.

CUARÓN: We used the cameras in the same principle as in Y tu mamá ...we decided social environment is as important as character, so you don't favor one over the other. That means going loose and wide. The camera doesn't do close-ups. Rather than make tension between the character and the environment, you make the character blend in with the environment.

The other rule of Y tu mamá ... is not to use montage and editing. Rather, it's to create the moment of truthfulness, in which the camera happens to just be there in time to register what's going on.

I didn't want to glorify or fetishize violence, I wanted to present it with the crudeness it has. The whole thing is trying to be truthful, so we went with a lot of references from documentaries. The explosions were like real-life explosions.

There's a tendency in movies to have spectacle explosions, with orange balls of fire. We also got experts who showed us the way people die. There aren't big stunt deaths in Children of Men where the bullets riddle a character and make them crash through a window. It's more banal: people falling down.

We saw a lot more than documentaries, footage from the different fronts—we wanted to absorb the new technology into this idea of the future. We watched Pontecorvo's The Battle of Algiers made with the technology of that time [the late 1950s], with a camera that was relatively less portable. In our film, we have a camera with no weight at all; the cameraman, is running around with it and can leap behind a wall. Sheltered, he can stretch his arms to still have a view with the lens.

When we watch the news from say, Baghdad or northern Sri Lanka, it's usually five or seven seconds of this stuff. But the video cameras are actually on all the time. There's a lot of mobility, but you won't see that in the news—the camera that's going from niche to niche trying to find the right angle. They're in constant motion.

METRO: About the actors ...

CUARÓN: As well as his being the star of the movie, I consider Clive Owen a co-writer. I feel that way about Julianne Moore and Michael Caine, too, for the way they shaped their characters. I was just so lucky to witness these actors at work. Caine wanted to play his role as an older John Lennon ... he knew John Lennon, they were friends. The actors understood we were doing long shots. When you're doing that, the weight falls on the shoulders of the actors. You don't have the safety net later on to speed up the scene, or widen it or change performance—all the weight falls on the actors. If anything works in this movie it's because of these guys.

METRO: A last, silly question: did Salma Hayek ever see the diving board masturbation "Salmiiita!" scene in Y tu mamá también?

CUARÓN: She is my sister, Salmita! (laughs) I told her about this tribute to her before I filmed it. She was laughing: "it's a beautiful image!"

Send a letter to the editor about this story.