Human rights groups have accused Beijing of ramping up its assault on civil rights activists after a respected lawyer was jailed for 12 years on what they claim were trumped-up charges. Xia Lin, a 46-year-old lawyer whose clients have included dissident artist Ai Weiwei and free speech champion Pu Zhiqiang, was detained in November 2014 and put on trial for fraud in July. The harsher-than-expected sentence was delivered on Thursday morning by Beijing's Np Two intermediate people's court, Xia's lawyer, Ding Xikui, told the Guardian. Activists and members of China's legal community expressed perplexity and outrage as they learned the severity of the sentence. "12 years!!! 12 years!!! 12 years!!!" Yaxue Cao, a US-based activist, wrote on Twitter. The Chinese Human Rights Defenders group described the sentence as "severe retaliation against a human rights advocate who defended the rule of law". Ding, Xia's lawyer, said he was "very disappointed" by the sentence and said his client would appeal. He said Xia believed he was being punished for representing Guo Yushan, a prominent activist who was detained in 2014 after voicing support for pro-democracy street protests that were sweeping Hong Kong. "He thinks they are taking revenge on him for getting involved once in the Hong Kong[case]... and some other human rights cases," Ding said, describing the sentence as unfair. Patrick Poon, Amnesty International's China researcher, said: "I'm extremely shocked." He said Xia's supporters were convinced his imprisonment was part of an ongoing attempt by the Communist party to silence dissent. He noted that the lawyer was known as a moderate member of China's once vibrant community of human rights lawyers. "It's really obvious that it seems to be politically motivated." "We can only see a very grim future for lawyers in China who work on human rights cases," Poon added. "It[underlines] the current regime's attitude to human rights activists ... It suggests that Xi Jinping's regime[has decided to take] a very heavy hand towards lawyers." Maya Wang, a Hong Kong-based activist for Human Rights Watch, said: "The harsh sentence against Xia Lin sends the sternest warning yet to the community of human rights lawyers, who has been under a sustained crackdown in the past year. President Xi has made clear that the law is "a knife held firmly in the hands of the party; Xia Lin appears to be one of its latest victims." Diplomats and long-term China watchers say they have been shocked by Beijing's growing intolerance of dissent. After Xi Jinping took power in 2012, police launched a severe crackdown on civil society and human rights lawyers, arresting and jailing a succession of lawyers and activists. Earlier this summer a series of show trials were held in the northern city of Tianjin at which defendants were paraded before the cameras to admit they had been attempting to foment a "colour revolution" in China. Many describe the current attack on free speech as the worst since the period following the 1989 Tiananmen crackdown. Speaking before Thursday's sentencing, Jeff Wasserstrom, a professor of Chinese history at the University of California, Irvine, said: "I'm really distressed. I'm more discouraged by political trends in China than I have been since the early 1990s and I think I'm not alone in that." Wasserstrom, the editor of the recently published Oxford Illustrated History of Modern China, recognised that Chinese citizens still enjoyed greater political and personal freedoms than in the dark days of Chairman Mao. "It's not that there has been a sudden, complete dropping down of this curtain that is blocking out all signs of life within China. There are lots of things going on still that are different from what you would see in a genuinely totalitarian setting. There still are protests that aren't met with horrific force. There are some topics such as environment that people can speak out about and do a little bit of organising for even, as long as it doesn't reach a large level," he said. "But the trend lines, that seemed to be moving in an at least gradually encouraging direction, just don't seem to be going that way anymore." Faced with a slowing economy and widespread popular discontent, Wasserstrom said China's communist leaders appeared to have decided their country now needed to live under a near permanent "state of control".