When Frank Poulsen, director of Blood on the Mobile, visits Nokia's headquarters in Finland, the landscape is snow-covered. The offices are antiseptic, hi-tech and apparently welcoming.
At least they are until he asks where Nokia gets the minerals for its telephones from. Suddenly every door closes and Nokia's pride in its social responsibility begins to look more than a little tarnished.
Poulsen asks himself the same question as he handles his favourite Nokia mobile in Copenhagen. From there he follows a trail to the Congo in his search for an answer to his simple - but controversial question - what is the source of the cassiterite used in the phones? His visit to the Congo, where five million dead has awoken little or no interest in the Western media, provides the shocking and infuriating answer. The minerals are mined by children without even a semblance of safety measures or unionisation.
These mines are armed camps run by the private armies from the eastern Congo where life is cheap, and easily bought and sold. The children are working for days on end in the unbearable heat of the mines. The enormously profitable mineral mining trade maintains and finances war, exploitation, and the abuse of women that has left 300,000 rape victims in the region.
So no matter how crisp and clean Nokia's headquarters, its social responsibility does not extend to refusing to buy these minerals despite the enormous human costs of their extraction. Apparently that's not its problem.
Poulsen's film belongs to a collection of campaigning documentaries that are closely linked to international campaigning organisations and the more radical NGOs. Their success, therefore, cannot be measured in commercial or even aesthetic terms. The purpose of such documentaries is to arouse interest in issues and encourage people to join campaigns.
Cassiterite is just one mineral. But we live in an age of massive and rapid expansion in mining and the growth of new mining multinationals that are driving indigenous peoples off their land in Latin America in the frantic search for the profits of the new mineral market. The world demand for copper, for example, has generated a new mining fever as demand from countries like China rises at a dramatic rate. The result is water pollution, land theft, climate change - and as in the Congo the exploitation of child labour and a new, 21st century slavery.
Poulsen's film is a weapon in the fight against this remorseless exploitation, and an exposure of what lies behind the face of multinationals like Nokia.
Blood on the Mobile is directed by Frank Poulson and is out now