Chinese activist Feng Zhenghu held under Shanghai house arrest Feng Zhenghu's supporters say up to a dozen guards monitor him day and night. Photograph: Ming Pao Daily News A Chinese activist angers the authorities by helping people use the law to protect their rights, and ends up trapped inside his home for months. So far, so familiar. But Chen Guangcheng is now living freely in the US. Feng Zhenghu remains under house arrest in his third-floor flat in central Shanghai. Since February, the 57-year-old scholar has been barred from leaving his home, except when escorted to the police station for 10-hour sessions - as he was on Saturday. At one stage, unable even to shop for food, he resorted to lowering a basket from his window for well-wishers to fill with groceries every few days. What they have done to me is a breach of the law. It has no legal basis. I am very angry," said Feng, speaking to the Guardian by telephone. Wang Songlian of Chinese Human Rights Defenders said: "Maybe people think Chen Guangcheng's case was unique and that this has been won. Feng Zhenghu and Chen's cases are both extreme, but they are on a continuum of illegal punishment and detentions for activists that is very, very common in China. Chen and his family were subjected to an extraordinarily vicious and sustained regime of house arrest. His wife was prevented from leaving home and the couple say they were beaten repeatedly. Even their six-year-old daughter was escorted to and from school by guards. But while Chen was being held in a remote village in eastern Shandong province, Feng is in the centre of arguably China's most developed city, across the road from a glossy shopping mall. It is not Shandong province here. It is Shanghai, a metropolis, but such things are still happening," said Feng. They know what they are doing is wrong, but they still keep doing it. I can take the pain; this incident is a good education for the public. It is difficult to establish an adequate system of law in China and requires more effort. Supporters believe the authorities see the parallel with Chen, too. They say officials installed the two rows of metal spikes below Feng's window, apparently to prevent him from escaping, shortly after the blind activist fled to the US embassy. On Thursday, a police car was parked beneath Feng's window and several men were watching the block. Supporters say up to a dozen guards monitor him day and night. Feng is used to battling officials: in 2009, he made headlines around the world by camping out at Tokyo's Narita airport when Chinese authorities stopped him from returning to his own country eight times. Many compared his case to the film The Terminal. After three months of high-profile protest, he was finally able to re-enter China. But since then he has experienced repeated harassment, including numerous bouts of detention and more than 10 searches of his flat. He believes the official resentment over his protest is partly to blame for his predicament, but says they are also angry that he helped other citizens to protect their rights. "I exposed the unfairness of Chinese administration of justice and that has put pressure on local officials," he said. Cui Fufang met the activist when he helped her seek compensation over the demolition of her home. Now she is one of several petitioners who regularly gather beneath Feng's window to show their support. He helped so many people to get their legal rights. He was helping the country by protecting its dignity," she said. Police have never formally notified Feng he is under house arrest. An officer at the local station referred queries to the Shanghai police media department, where calls rang unanswered. We do not have conclusive data, but my impression is that [house arrest] has been more favoured by the government since the Olympics. It doesn't elicit such a reaction from the public as putting people in prison," said Wang. Liu Xia, the wife of jailed dissident Liu Xiaobo, has been under house arrest since the announcement that her husband had won the Nobel peace prize in October 2010. Grassroots democracy campaigner Yao Lifa has been held for shorter periods many times. Other dissidents and activists are often kept under "soft detention" at sensitive times - allowed to leave their homes under escort, but not to move freely or receive visitors. "My freedom is not important," said Feng, from his flat. Whether China can be a country ruled by law is more important.