Chen Wei's sentence appears to be the most severe punishment handed down in a crackdown on dissent this year

A Chinese court has sentenced a veteran democracy activist to nine years' imprisonment for inciting subversion, in what appears to be the most severe punishment handed down in a crackdown on dissent this year.

Chen Wei was convicted of incitement to subversion over four essays he wrote and published online, according to one of his lawyers. He was detained in February amid an extensive government crackdown in response to anonymous online calls urging Chinese to imitate protests in North Africa and the Middle East.

Attorney Liang Xiaojun said the trial at a court in the city of Suining in south-west China lasted about two and a half hours and the sentence was handed down 30 minutes after the trial concluded.

"We pleaded not guilty. He only wrote a few essays. We presented a full defence of the case, but we were interrupted often, and none of what we said was accepted by the court," Liang said.

Liang said that after the sentence was handed down, Chen said: "I protest, I am innocent. The governance of democracy must win, autocracy must die."

Chen's wife Wang Xiaoyan denounced the punishment.

"He is innocent and the punishment was too harsh. The court did not allow him to defend himself and he was completely deprived of his right to free speech," Wang said by phone from Suining. "What's wrong with a person freely expressing his ideas?"

Chen, 42, previously served time in prison for participating in the 1989 Tiananmen Square pro-democracy demonstrations in Beijing, where he was attending college. In 1994, Chen was sentenced to five years' imprisonment for "counter-revolutionary propaganda and incitement," according to the court indictment for his subversion charge.

Friday's sentence handed down to Chen appears to be the heaviest penalty meted out in relation to this year's crackdown, said Wang Songlian, a researcher with the Hong Kong-based advocacy group, Chinese Human Rights Defenders.

"This severe punishment against an activist, caught up in the Jasmine crackdown, shows how the Chinese government's nerves are still jittery," said Wang.

"All its latest moves, its attempts to control its microblogs, its crackdown on activists, show it is increasing tightening on freedom of expression and other civil liberties," she said.

Others rounded up in this year's crackdown who have been punished include Beijing activist Wang Lihong, who was sentenced to nine months in jail in September for staging a protest on behalf of other activists, and Yang Qiuyu, a Beijing activist who was sentenced to two years of re-education through labour.