The Spanish name for the award-winning Mexican film The Golden Dream is La Jaula De Oro, which translates as cage of gold.

“It’s what the migrants call the US because of all the gold, all the money, but when you’re in it it’s like a prison,” explains the quietly spoken 45-year-old director Diego Quemada-Diez.

The film reflects how free trade agreements with the US, combined with decades of intervention and destabilisation in central America, have caused profound inequality, poverty and violence, provoking millions to flee north.

The film follows four such youngsters as they make the treacherous journey from Guatemala to the US.

“I want to make films that are entertaining, epic action films, but that make us think about our human condition, to make some kind of positive transformation of our society by transforming the viewer,” says the director, whose first feature film job in Spain was on Ken Loach’s Land And Freedom.

“What I am trying to do is give a voice to the oppressed. As [Cuban director] Tomas Gutierrez Alia says there are two kinds of cinema — the mainstream is trying to maintain the status quo while another kind of cinema inspires rebellion.”

Getting the film made required herculean dedication and vision. “It was a very complicated film to make,” Quemada-Diez explains, in something of an understatement. “There was a crew of 40, we had 120 locations and several thousand extras. We were always moving, sleeping every two days in a different place. We could never go back. We were in a country that was almost in a war situation so you had to be very careful.”

The casting itself was an epic undertaking, following the director’s deeply held aim to find non-professionals from the poorest parts of Guatemala and Mexico for the lead roles. 

“I saw over 6,000 kids for a period of nine months. The first thing they say is ‘I want to go to America.’ And because I wanted to make a film about migration as an economic issue, I decided to find the lead actors in the most impoverished and violent places in central America.

“From talking to migrants I realised there was an internal image of what they thought the US was like. They talked about the skyscrapers and the grass is well cut and beautiful, everything is green and streets clean.”

In one of the many striking scenes in the film, a migrant who is travelling on the top of a train through Mexico sings a song which seems to express the philosophy of the film and its director: “Brothers in this world no-one is better than anyone else, we come from nothingness and we go back to nothingness.”

What appears to be a beautifully directed and written scene was actually simply a case of the camera being in the right place at the right time. “All the people on the train are real migrants on their way to the US and we are right there with them. And this guy starts singing and I thought ‘he’s got to be in the film’.”

Racial prejudice on the part of  Juan, a white Guatemalan, toward indigenous migrant Chauk gradually gives way to a powerful bond in the face of adversity. “In Chauk we have a character whose language we didn’t understand,” the director says. “But we could still understand him — the idea is that beyond nationality, beyond language, beyond colour we have something in common and to realise that language is not so important. You could tell when he is upset, when he is in love.”

Ultimately their dangerous journey brings them to the US but there’s no happy Hollywood ending. Juan, the protagonist, ends up working in a meat factory — a typical job for migrants. 

“I was clear I wanted to show the US as a grey and ugly place full of freeways, concrete, asphalt, coldness and darkness because that model, if it continues like this, is going to destroy the entire planet. The entire Earth will become one big shopping mall with concrete freeways.”

Quemada-Diaz devoted seven years to researching the project, spending months on the migrant railway routes collecting testimonies from those who undertook the perilous journey. In the US he went to prisons and migrant detention centres to hear stories of separation and police brutality.

On several occasions he had a gun pointed at him. “I stayed with a friend who lived by the railway tracks in Mexico and for three or four years I would go and stay with him to do the research and eventually we had a problem with a local drug dealer because we didn’t ask his permission and he thought we were drug dealers. 

“He was going to take us to a field and shoot us. We had to convince him and eventually he let us go.” 

Since its release the film has become a hit in the slums of Mexico and Guatemala but in pirated form. 

The director seems pleased that the film has reached the people whose neglected lives it has dramatised. 

“It’s everywhere. People are loving the film and actually in working-class neighbourhoods it’s done best. It
gives them a voice — they are the protagonists and they are really happy about it.”

Meanwhile on the festival circuit in France, the US, Cuba and India it has been showered in awards. In Cannes the entire ensemble cast won the Un Certain Regard best talent prize. “It’s a beautiful thing,” he says. “They feel so empowered.”

The Golden Dream is now on general release.