Follow the tiger: How one man led Chinese dissidents to safety in Hong Kong

Sitting in his home on the campus of Sichuan Normal University at Chengdu, Gao Ertai wondered when he would be free from fear.

It was 1992, three years after China's bloody crackdown on Tiananmen Square marchers. Gao, a painter renowned in China, had previously spent six years in a labour camp. After Tiananmen, he was sentenced to four months in prison for carrying out seditious acts. The thought of losing his freedom gnawed at him.

Finally he passed a message to his close friend, the author Zheng Yi, that he wanted to flee to Hong Kong, as Zheng had done a few months earlier.

"It is risky to flee, but it is even riskier to wait," Gao wrote. "Rather than hoping for enemies' negligence and friends' loyalty to live a helpless life on tenterhooks, it would be better to follow the unknown fate."

He was surprised when he heard a knock on the door and found a stranger from Hong Kong standing outside. Until that moment Gao had never thought he would permanently leave his homeland.

Gao was one of 40 dissidents rescued by this young man from Hong Kong - a man who preferred to be called Tiger in an interview with the South China Morning Post.

He and many others took part in "Operation Yellow Bird", one of the most legendary underground activities backed by the Hong Kong Alliance in Support of Patriotic Democratic Movements in China.