Beijing: The director of the law firm at the centre of China's sweeping crackdown on lawyers and rights activists has been sentenced to seven years in prison for subverting state power.

Zhou Shifeng, of the Beijing-based Fengrui Law Firm, is the third legal rights advocate to be convicted in as many days as part of a four-day Communist Party show trial in the northern city of Tianjin.

As with the two men tried before him – Hu Shigen and Zhai Yanmin – Zhou, 51, was refused his own legal representation and assigned a court-appointed lawyer. His family was barred from the courtroom and the judges handed down their verdict and sentence within hours of the trial commencing on Thursday.

Zhou and his associates are the first group to be tried since a wide government crackdown that began last July led to more than 300 lawyers and activists being detained and interrogated. Of those, about 20 have been formally arrested and charged.