The Walled City has changed since Jackie first entered it. Successive police crackdowns in the 1970s and 80s have brought a semblance of control to the area, and yet the Walled City is still an area of great poverty.

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 sceptical 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 realise 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.

Next: Opposition and success