On the outskirts of Chaman, a town in Balochistan on the Afghan border, there is a compound with high mud walls topped with broken glass. A worn Pakistani flag flutters above the steel gate and on the dusty ground, under a hot sun, sleeps a well-fed guard dog. This is the headquarters of the Haji Janan Trust, a unique organisation dedicated to waging war on drugs.

“It all started when my childhood friend began taking heroin,” recalls Haji Janan, the local businessman who set up the trust. He is lean, middle-aged, with strong features and an impressive grey turban. “I became so angry one day that I just took him and threw him into the cellar in my shop. I kept him locked up for three months. When I took him out, he was cured; he was so happy. We worked on two more of our friends in the same way. Then, we decided to make this our mission.”

Chaman is one of only two crossings on the Pakistan-Afghan border used to transport supplies to Nato troops in Afghanistan. It is also a militant hideout and a major opium conduit. Here, heroin is cheap and plentiful. Opium from Afghanistan is smuggled through Balochistan, the largest, poorest province in Pakistan, and into Iran in huge quantities. The officials and security forces charged with stopping the drugs trade are thin on the ground and notoriously corrupt. “They take payments weekly,” says Haji Janan, then grins: “They don’t like us much.”

“We punish drug dealers,” says Ibadullah bluntly. A powerful man in a tight-fitting army T-shirt, Ibadullah was a heroin addict until Haji Janan found him. Now he is part of a vigilante squad working undercover to clean up Chaman’s streets. “When we catch a dealer,” he explains with relish, “we hang him from his hands and beat him. Sometimes we burn his house down.” Two Kalashnikovs hang on the wall behind him, surrounded by posters of flowers. “We are like suiciders when we do this work; we have no thought for our safety.”

There are currently more than 200 addicts being treated in the rough dormitories surrounding the courtyard. In one room 30 men lie on thin mats. It is easy to spot the new arrivals: they are listless and wasted, and their eyes are puffy. But despite the tough conditions, none of them wants to leave.

In eight years more than 5,000 addicts have been treated. Some were brought by relatives, some snatched from the streets, and others came of their own accord. For all of them the treatment was the same – confinement and prayer. “We have one simple formula,” says Haji Janan. “I think, of the people we have treated, just 500 have gone back to drugs. When someone leaves, we help him to find a job.” Now, people are starting to arrive from as far away as Karachi and Helmand in search of a cure. There are more than four million drug addicts in Pakistan, half of them heroin users, and free treatment is hard to find.

Funded with donations and by Haji Janan, the trust relies on volunteers, nearly all of whom were once addicts. In the kitchen, making flatbread, is Abdur Kadir. “Before this,” he says, slapping raw dough against the hot sides of the wood-fire stove, “we were all patients. Now we have decided to do something for the people.”

“I have big dreams,” says Haji Janan. “If God helps me and I am strong I will open a centre in every part of Pakistan.”