Shanghai lawyer Zheng Enchong, a crusader for the rights of city residents displaced by property redevelopment, has lost his appeal against a three-year sentence for theft of state secrets. But the legacy of his work is still being felt in one of China's most lucrative private real estate markets, where housing inequalities are becoming too big to ignore - and are increasingly being worried about as a source of potential social instability. Some district officials and private developers, including Chau Ching-ngai, previously Shanghai's richest businessman, had clearly been amassing wealth by circumventing requirements for open tendering and compensation to tenants. Such practices are now being curbed and city government officials have been stepping in to make the property market more equitable. This has involved reinforcing rules on auctions for the transfer of development rights and the release of parcels for low-income housing projects. Chau has been arrested and his empire is in the midst of being broken up. Meanwhile, bank officials implicated in his various schemes have been investigated. Sadly, the lawyer who helped bring the problems to light and set the reforms in motion is sitting in jail. His conviction, which was upheld on appeal by the Shanghai Higher People's Court last week, rests largely on the release of information about one of Chau's projects to the New York-based group Human Rights in China. There is evidence to suggest that not everyone in the national leadership is entirely comfortable with the way this case has turned out. Unease with the use of state-secrets laws to convict Zheng extends to the State Council's Development Research Centre, whose publication, China Economic Times, criticised the classification of eviction and property market problems under the umbrella of state secrets. It is a point well worth closer examination. Beyond the legal justifications for Zheng's imprisonment, there are other questions that have been raised about the conduct of the case. The trial was conducted behind closed doors, and even the appeal was denied an open hearing. Instead, Zheng's lawyers were told at the last minute to submit their appeal as a written statement. Last month, his wife was allegedly harassed while travelling to Beijing to consult their lawyer and was sent back to Shanghai before she could speak to anyone. These events raise troubling questions about whether Zheng was given due process and subjected to the rule of law. For Hong Kong, the case has another dimension. In light of revelations that the former secretary-general of the Beijing Liaison Office here may have been spying for Britain, there have been renewed calls for the city to pass national security laws that protect the government against subversion and the release of state secrets. But as long as such laws are allowed the kind of broad interpretation applied to Zheng's case, there will be resistance to their enactment here. Hong Kong residents will need convincing that such laws will not be used to curb the freedoms they now enjoy, and there will be calls for built-in safeguards. As the mainland's economy continues on its path of market-oriented reform, policymaking has been geared towards spreading the benefits of new-found prosperity more evenly among citizens and stamping out the pockets of corruption that have flourished in grey areas of the law. The new leadership has been particularly outspoken in this regard. Justice for Zheng would be in keeping with that agenda. More than that, achieving it is one way of convincing the sceptics that timely passage of national security laws is nothing to be worried about in Hong Kong.