A Chinese dissident is risking jail to publish a new book that debunks one of the central myths of the ruling Communist Party: it claims that Premier Wen Jiabao's image as a kindly, caring grandfather if the nation is a sham.

The picture of tearful "Grandpa Wen" standing on the rubble in Beichuan after the 2008 earthquake that claimed 80,000 lives, exhorting rescuers to work harder and comforting survivors, did much to shore up support for the Communist Party at the time.

Last week he was again on the front line, standing in the mud of Gansu, hugging the families of victims and rallying rescuers at the site of the mudslides in Zhouqu. The way he sheds tears at the disaster sites and embraces those who are HIV-positive has earned him a reputation as a genuine man of the people.

But Yu Jie, the Beijing-based 36-year-old author of Wen Jiabao: China's Best Actor, said Premier Wen was simply playing a role, acting as a mediator between an authoritarian government and its citizens in order to hold the party together. The book, which has been published in Hong Kong, also attacks the suggestion that Premier Wen is a progressive figure, or a reformer.

"There is only one objective for all that Wen Jiabao has done since he took the reins, and it is to 'act'. He knows that this old car – the Chinese Communist Party – is going to fall apart," says an excerpt from the book.

There is little new research in it but the opinions contained in it are not generally openly expressed in China.

"Even today there are still many people who believe Wen is 'the people's good premier' who can't act on his plan because of pressure from certain interest groups," Mr Yu writes in one essay in the book. The dissident takes the example of the Sichuan earthquake, where Mr Wen promised the parents of student victims an investigation into the collapsed schools, but never delivered.

Mr Yu's views could cost him his freedom. He was interrogated by state security after news that he was writing the book leaked out, and was told that he could end up in jail like his fellow dissident Liu Xiaobo.

Mr Liu was given an 11-year sentence on subversion charges for airing his anti-government views in public and organising the Charter 08 pro-democracy forum. The police said that Premier Wen was not a normal citizen – he was the premier, so criticism was not allowed.

The fact that Mr Yu is publishing the book in Hong Kong could offer him some protection, because the Beijing government tends not to interfere in the freedoms enjoyed in the former British colony, which was returned to China in 1997.

It is being published by Bao Pu, head of the Hong Kong publisher, New Century Press, which often publishes politically sensitive and controversial books. Mr Bao said he had not had any unwanted police attention during the publishing process, although he did write in his introduction to the book that the author had been warned. "Criticising the leader is a very serious criminal case," he wrote. "It would be very likely for [Mr Yu] to be punished severely like the way Liu Xiaobo was."

The book pulls no punches on the issue of public criticism of the government. "Accepting criticisms and scolding from the public is the very first basic skill a ruler needs to have. Without such mental quality, one should not take part in this game." Without a popular mandate, the Chinese government has to "force its people to recognise it by force and lies," he wrote.

Premier Wen appears to have an uncanny ability to generate sympathy. Earlier this year, he revealed that his mother suffered a brain haemorrhage last year when she watched television footage of a student throwing a shoe at him during a visit to Cambridge University. He is also a cunning politician.

He was with the disgraced former leader, Zhao Ziyang, on his last public appearance on May 19, 1989, when Mr Zhao visited student demonstrators in Tiananmen Square, in front of the Forbidden City, to talk to them. Mr Zhao's sympathy for the students cost him his job and his freedom, but Mr Wen managed to come back from political oblivion to become premier. The book will be available in English soon.

Literary voice of protest

The soft-spoken writer was a best-selling author – his first volume sold 2 million copies – before his books were banned from mainland China not long after Premier Wen came to power in 2003. The 36-year-old helped found the Independent PEN Centre in China and as a devout Christian has angered authorities by advocating religious freedom, including defending the Beijing government's bête noir, the Dalai Lama.

Yu Jie has a degree in literature from the prestigious Peking University. His productivity as a political writer has earned him a special place among Chinese dissidents and no one can quite believe how he has stayed out of jail for so long. He once proposed that Mao Tse-tung's body be removed from the mausoleum on Tiananmen Square.

Yu now publishes his books either in Hong Kong, Taiwan or in Chinese in North America. If his work on Mr Wen is published in the US it is bound to have a major impact on opinion about the Chinese leader. It may take longer however for the shock waves to reach Chinese readers as the majority of readers will be denied access to its content.