China on Tuesday sentenced human rights activist and blogger Wu Gan to eight years in prison for allegedly subverting state power, Reuters reported. His sentence is the harshest since the government began a crackdown on activists in 2015.

Wu, better known by his online name “Super Vulgar Butcher”, will appeal against the verdict, his lawyer said.

He regularly wrote online and held street protests against the government’s abuse of power. He was detained in May 2015 soon after he expressed doubts on the official version of events about the shooting of a civilian by a police officer.

The court said that Wu had criticised China’s political system online and used performance art to create disturbances as well as insult people and spread false information. “He carried out a string of criminal actions to subvert state power and overthrow the socialist system and seriously harmed state security and social stability,” the court said.

The decision to hand down the sentence a day after Christmas, when foreign diplomats and observers would likely not pay much attention, “reeks of cynical political calculation”, said Patrick Poon, Hong Kong-based researcher for Amnesty International.

More than 200 people, including civil rights lawyers and human rights activists, were detained in the so-called “709 crackdown” in 2015, according to the BBC.