This is what Jackie Pullinger did. Jackie Pullinger began to make this huge decision early. As a young girl at Sunday School she decided she wanted to be a missionary - and that was before she really knew what a missionary was. But as she grew up, she forgot about her childhood ambition for a while and became a student at the Royal College of Music.It was only when she started meeting regularly with other Christians in a friend's home that she thought about being a missionary again. Then one night, she had a dream."I saw a vision of a woman holding her arms out beseechingly as on a refugee poster. I wondered what she wanted - she looked desperate for something… Then words moved past like a television credit: WHAT CAN YOU GIVE US?"

After a series of dreams and vivid experiences, Jackie decided she would go to Hong Kong. The trouble was, no one else agreed with her.

She applied to every missionary group she could think of, and also to church organisations and the Hong Kong government - but all the doors closed in her face. You're too young, you're too inexperienced, you have the wrong qualifications, she was told.

She was about to give up, when the vicar of a church she helped in told her, against the received wisdom of everything else she had heard, to go to Hong Kong anyway.

In 1966, Jackie Pullinger gathered up all the money she had and bought a passage on the cheapest boat to Hong Kong she could find. She only had enough money for a one-way ticket, so there was no turning back.

She almost didn't make it past Hong Kong immigration. But she was eventually allowed in and found a job teaching at a primary school in the Walled City. This was an area where the Hong Kong police had no regular jurisdiction. As a result, it was Hong Kong's most deprived and dangerous area.

Triads, dragons …and faith

Running the Walled City were the Triads: Chinese secret societies which degenerated into criminal gangs. Nothing happened in the Walled City that the Triads did not know about, or exact payment for, or respond to, with a show of violent force.

They have sometimes been equated with organisations such as the Mafia. At a street level, they are loosely-connected gangs who make money by various illegal means and command fear by employing blackmail and violence. Among the fifty or so known societies, membership is extimagted at anything up to 100,000 - maybe more.

The original Triad Society is popularly believed to have come into existence in the seventeenth century to restore the Ming Dynasty after its overthrow by invading Manchurians in 1644. Triad history also reaches further back to the old secret societies in China, which were concerned with the journey of the spirit toward heaven. The traditional initiation rites of the Triad Society included learning poems, hand-signs, and shedding and drinking blood.

The original aim of the Society was seen to be fulfilled in 1912, when Dr Sun Yat-seen established the Republic and made a declaration at the Ming Tombs that the Manchus were finally overthrown. Subsequently, the Triads enjoyed a measure of prosperity in the new China, but ultimately degenerated into crime. When the Communists were victorious in 1949, many fled to Hong Kong to continue their criminal activities alongside compatriots who were already well-established: Hong Kong had reputedly become the headquarters of the Society as far back as 1845.

But in 1966, it was far worse. Many of its inhabitants could only scratch a living by slaving in sweatshops under appalling conditions. Others became prostitutes or sold drugs. All of them lived in fear of the infamous Triad gangs – even though most of the gang members were just teenagers.

Outside her primary school job, where she taught music, Jackie started approaching people in the Walled City to say that Jesus loved them. Most of the people she talked to were either politely condescending or just amused.

Then Jackie set up a small youth club. Many of the boys who came to it were members of the Triad gangs. To begin with, the people of the Walled City were skeptical of her – missionaries came with lots of money and nice clothes and preached and helped for a while before going home to the West. Many people simply couldn't believe that Jackie had no money and wasn't going to go away.

Eventually, she gained the trust of the young men, and they began to believe that she was there to stay, and that she meant what she said – that she really did care for them. She began to see the boys becoming Christians one by one. Many of them were addicts.

Opium and heroin abuse – "chasing the dragon" – was, and still is, an epidemic in the Walled City. In a 1989 interview, Jackie recalled:

"I could walk down the street and see a hundred people chasing the dragon. You had to climb over their legs. I wanted something real to offer them… not just treatment in a centre."

Despite the power of heroin and opium addiction, the boys weren't only kicking their habit, they were leaving it behind completely. They put this down to their commitment to Jesus. Many addicts who prayed for Jesus' help found themselves freed of their addiction without going through any kind of withdrawal. Jackie opened a home for those who needed help and was soon inundated with pleas for help and a place to stay.

Not all of the addicts reformed immediately. Jackie started to realize that becoming a Christian didn't automatically heal you of your addictions, or immediately reform you after a lifetime in the underworld. But the signs were good.

Several reformed addicts joined Jackie in her work. Ah Ping, a Triad who became a Christian, went on to set up a rehabilitation centre in Macao.

Opposition and success

Jackie promised herself very early on that she would never ask for money for her work. But money started flooding in. She quit her school job and was offered monthly payments to support her work. She accompanied one of the boys from her house to court, and sometime later found was sent a large sum of money from the legal aid department, even though Jackie had never asked for legal aid, and tried to send it back.

Jackie's efforts to show and tell the love of Jesus eventually had an amazing degree of success. She also received help from some of the most unlikely places.

She won the trust and approval of the very groups she opposed: the Triads. After Jackie's youth club was destroyed by vandals one night, a Triad boss sent guards to watch the building and make sure it didn't happen again. This same gang boss later arranged a meeting with Jackie.

He told her that he didn't want his gang members to be addicts any more than she did. She had succeeded where he had failed and therefore he would support her as she helped to free get his men off drugs.

Jackie's response was uncompromising. She told him simply that she wouldn't help the boys escape their addictions purely for them to become gangsters again. If they were to be followers of Jesus, they had to leave the gangs altogether. To her astonishment, the gang boss still offered to guard her house, and renounced all claim on those boys who chose to become Christians. It was unprecedented in Hong Kong gang culture, where people were bound to the Triads for their entire lives.

As Jackie's work grew, she found herself able to open a second house. By the time a third home was needed, Jackie, with the help of a couple of American missionaries, set up the St Stephen's Society, which continues its work in Hong Kong and south-east Asia today.

The society has become one of the most successful drug rehabilitation programmes in the world, rescuing hundreds of young people from a life of misery on the streets.