But some researchers believe full legalisation could leave the women ostracised by society or struggling to make enough money.

Working as a prostitute is not illegal in Hong Kong. While soliciting clients and keeping a brothel are banned, so-called one-woman brothels are tolerated. But Shao says today's laws leave sex workers open to exploitation. With brothels outlawed, women cannot band together for protection. The migrants who have begun to make up the majority of prostitutes in the city face a further threat: if they approach the police, they are likely to face deportation for immigration offences.

Each quarter, Zi Teng records cases of robbery, police mistreatment, violence by clients and stories of handlers withholding pay. It believes more incidents go unreported, especially among migrant workers who lack a support system.

As well as offering protection, rights groups say legitimising prostitutes would offer psychological relief for the women, buoyed by the opportunity to seek help from the police.

Susanne Choi Yuk-ping, an associate professor at Chinese University, has studied the lives of prostitutes in Hong Kong, Macau and on the mainland. She found that Hong Kong prostitutes who were able to seek help were not worried about police raids. With the support of NGOs, they felt much less pressure than those on the mainland, where prostitution is illegal, raids more frequent and there is no support from rights groups.

Choi advocates full legalisation so that women can seek help without fear, and for their psychological welfare.

'Criminalisation is mostly penalising the women and giving opportunities to gangs to control the industry,' says Choi. The women, she says, are forced to find other means of protection.

While legitimising the profession may make sense from a welfare point of view, the economic argument suggests otherwise.

'Legalising prostitution may actually jeopardise the ability of these women to make money,' says Dr Victor Zheng Wan-tai, an assistant professor at Hong Kong University's Centre of Asian Studies. 'Many of them work in the trade without their family's knowledge. To legalise the trade means their family and community will know, which will cause them problems both in getting jobs and being accepted into their communities. Prostitution is seen as morally wrong. If these women's identities as prostitutes are disclosed, they may be ostracised by society.'

While prostitution was largely tolerated in Hong Kong's early years, when men outnumbered women three to one and there were few opportunities for women to find work, today's society is vastly different.

'There isn't as big of a need now as before - over half the population in Hong Kong is female, unlike the overwhelmingly young and single male population 100 years ago,' says Zheng.

'Hong Kong society today has changed drastically - the social make-up is very different from that in the 1850s. A strong sense of home and locality means community-building is more important for Hongkongers now, so morally problematic things - like prostitution - are no longer tolerated.'

Yeeshan Yang, author of Whispers and Moans, a 2001 book on the Hong Kong sex industry, agrees that the sex trade needs to stay underground to be profitable. 'When they come out in the open their price drops,' she says.

'In Amsterdam the women's prices dropped so much [when prostitution was legalised], they ended up going across the border to Germany knowing they would be undertaking all the risks.'

14

The maximum number of years in jail someone can get for organised prostitution. Anyone who solicits may be fined HK$10,000