Independent Appeal: Campaign to free the slaves of the Amazon

Earlier this month, a group of inspectors - they call them the Flying Squad - descended on a ranch at Pacaja in the remote Amazonian state of Para in the north of Brazil. There, they found 125 people living in makeshift plastic shelters, exposed to the rain. There was no sanitation. All they had to eat was manioc flour and any game they managed to kill. Three of them had malaria and several had untreated wounds from work accidents. Armed guards had stopped them escaping.

Their work was cutting down trees with electric saws for an illegal logging operation. They were held in debt bondage, obliged to pay exorbitant sums for tools and flour out of their wages - but they had not been paid for four months.

Slavery is outlawed in Brazil. Three years ago, the Brazilian government launched a campaign to eradicate the practice. Soon after the crackdown began, one government inspector, Marinalva Cardoso Dantas, led a raid on a cattle ranch in the state of Mato Grosso. It belonged to a Rio politician.

She found 41 men and women, among them a couple with a young child, Igor, who lived in the camp "like a tamed wild animal", denied the chance to go to school or to play with other children. "The workers were treated as inferiors, because of their poverty and illiteracy, living under plastic sheets," the inspector later wrote.

Since the crackdown began, many thousands of slave workers have been freed from Amazon ranches, sugarcane plantations and charcoal camps. But the practice continues in isolated regions, where the police are in the pay of the owners of the slave ranches. That is why the government has to use its Flying Squad to launch surprise raids on the slave camps.

As soon as the Flying Squad arrived at the ranch in Pacaja earlier this month, the ranch manager and the guards fled. Public prosecutors immediately calculated how much each worker was owed for his labour and ordered the landowner to pay up immediately. They will also sue him for a sum to compensate each worker forced into slavery for "moral damages".

The Flying Squad was set up in 1995 to be the teeth of an earlier attempt to clamp down on slave labour. The members are drawn from the ranks of Labour Ministry inspectors, men and women from all over Brazil. They have all volunteered for a difficult and dangerous job.

Very often it takes days to reach ranches in the remote areas of the Amazon rainforest. Their vehicles get stuck in deep mud, and often the Flying Squad travels by boat. Once, a woman inspector led a raid riding a tractor, the only vehicle that could cover the terrain. But these inaccessible places are where slave labour is most used.

The danger is very real. In January 2004, three inspectors and their driver were murdered as they investigated accusations of slavery against a powerful landowner in the state of Minas Gerais. After freeing more than 800 workers in Para in the first six months of 2002, a group of inspectors were held up by 12 heavily armed, hooded men on a road near Marabá and robbed of their equipment.

There have been attempts at bribery. Inspector Riccioti Piana, a doctor, remembers how during one raid, a rancher ostentatiously opened a suitcase full of banknotes. He had to use the money to pay a hefty fine for using forced labour.

Dr Piana, who has worked as a member of the Flying Squad for many years, described finding men with infected wounds bound up with dirty rags, and others with malaria and leprosy. He has found many workers in a state of malnutrition, some of them skeletal, suffering from calorie and protein deficiencies. On some ranches, the owners forbade workers to catch fish from "their" rivers. On a raid near the Trans-Amazonian Highway, inspectors found a worker whose legs had been crushed by a falling tree, abandoned without medical assistance.

The inspectors' task is to supply vital eyewitness accounts of the conditions in which they find workers, which then become vital evidence for bringing criminal charges.

The existence of the Flying Squad is a deterrent to ranch owners who exploit the huge pool of unemployed and illiterate workers to boost profits. But the inspectors' work depends on receiving tip-offs about where slave labour is being used. Most of this information comes from a non-government organisation, the Catholic Church's Pastoral Land Commission (CPT), which has a network of priests, nuns and layworkers throughout the Amazon. Its work is supported by Anti-Slavery International - one of the three charities for which funds are being raised in this year's Independent Christmas Appeal. Together, the two organisations campaign to prevent men and women being lured into slavery.

Anti-Slavery International has provided training to CPT and works with it to draw international attention to the issue of slave labour in Brazil.

The men and women of Brazil's Flying Squad have freed thousands of workers, and proved themselves an amazingly courageous and determined group of civil servants. But they still have a lot to do, which is why, as one member puts it: "I pray before each raid that I won't stop getting angry."