In the past week Ng, a devout Catholic, trekked through the city alongside retired cardinal Joseph Zen Ze-kiun to encourage participation in the unofficial plebiscite on universal suffrage that began yesterday. Wong volunteered with Occupy on the campaign's first day of recruitment in March.

And if the government's proposal for electing the next chief executive in 2017 doesn't meet international standards the pair will join other activists, led by University of Hong Kong legal scholar Benny Tai Yiu-ting, to obstruct thoroughfares in Central.

For Ng, going to jail - a likely consequence for the participants - is nothing to fear.

Cells are nothing new to him.

A Hong Kong resident, he was locked up during the lawless Cultural Revolution when he went to visit his ailing father in Leizhou , the Guangdong peninsula opposite Hainan , in 1968.

The communists detained him for three years and seven months on the grounds that he was a Catholic and - due to his background as a Hongkonger - a suspected spy. "Inside, prisoners ate salted fish that even cats wouldn't try. You worked in return for 50 cents a day," he recalled.

"I thought to myself: 'I'd rather be a dog in Hong Kong than a human on the mainland'. When I was incarcerated, it was really like walking in an endless tunnel with no light ahead."

Born in Leizhou, Ng was sent to a missionary school in Guangxi , then, after the communist takeover, to Vietnam, at that time a French colony. Upon his boat's arrival in Haiphong, he was assigned to clean metal on board French warships, until he was settled in Hanoi. Shortly afterwards he had to flee the communist army led by Ho Chi Minh.

Back in Haiphong he took a plane to Hong Kong's Kai Tak airport, his first visit to the city he would later call home. He went to secondary school in Macau and upon graduation returned to Hong Kong, working various jobs before he began a 30-year career as a cabbie, interrupted by his jail stint on the mainland.

Ng said his life told a story where pessimism had no place - just as Hongkongers needed to have faith even when Beijing appeared to be toughening its line on the city.

"If Beijing offers us something really bad, the Legislative Council won't allow it to pass," he said. "We still at least can try it all over again."

Form Five student Wong, who aims to study law, said he was dissatisfied with the way some of his peers immersed themselves in study without regard to society.

"However hard you study, whatever achievements you make, it's meaningless if you live in an unjust society," he said.

Lately he has been encouraged by influencing his relatives to discuss the campaign and the way forward. But a question mark remains for him over whether the wider community will offer as much support.

"If Occupy protesters end up arrested by riot police and people wake up the next morning going to work, thinking about investments and shopping at wet markets just as any other day, Hong Kong will be done."