A Chinese college professor was jailed for nearly four years today for running a swingers club and holding private orgies

Ma Yaohai, 53, was convicted and sentenced on charges of group licentiousness , said an official from the Qinhuai District Court in south-eastern Nanjing.

Ma, along with 21 other people, was arrested and charged last year - the first time anyone has been charged under a 1997 law.

Ma's lawyer Yao Yong'an said his client, who was the only one to plead innocent, plans to appeal.

"It's definitely not a fair case. It's not based on the law ... We can understand the reason behind it, but we can't accept it," he said.

Three of the other defendants were acquitted with no penalties because they turned themselves in, the official Xinhua News Agency reported, while the remaining 18 received jail sentences up to 30 months. One report said they got lighter sentences than Ma because they demonstrated "good attitudes" by pleading guilty. The maximum sentence for the crime was five years in prison.

Prosecutors had accused Ma, a computer science professor at Nanjing University of Technology, of organising a swingers club, where members met online and gathered in private homes or hotels for group sex parties.

But Ma maintained he committed no crime, arguing his activities involved consenting adults meeting in non-public places.

His defiance seemed to strike a chord in an era of relative sexual freedom, where extramarital affairs and prostitution are common - drawing support from those who believe the Chinese government should stay out of the bedroom.

Chinese have debated whether the country's laws on sexual behaviour were outdated in a society that had undergone stark changes in its attitudes toward sex.

Sociologist and sex expert Li Yinhe, who was among the most vocal public defenders of Ma, said she was disappointed in the court's ruling, adding, "Ma Yaohai shouldn't be sentenced at all."

She acknowledged the sentence marked an improvement compared with 20 years ago, when displays of public affection and even dancing with members of the opposite sex could be punished.

"He could have been sentenced to death then. But the real improvement should be the complete abolishment of this crime," she said.

With rising prosperity and an easing of government controls on personal freedoms, China has moved toward a more progressive view on sex, though attitudes remain more traditional in the countryside than in urban centres.