The son of a prominent Chinese human rights lawyer has been barred from leaving the country for a holiday in Japan because he “could potentially endanger national security”, his father said on Tuesday. Border control officers at Tianjin Binhai International Airport stopped Bao Zhuoxuan, the 18-year-old son of lawyer Wang Yu, from leaving China on a Tokyo-bound flight on Monday afternoon, his father Bao Longjun said. Bao Longjun, who went to the airport to see his son off, said the officers stopped the teen at a border check and held him for more than an hour. He was eventually released after the officers invalidated his passport by cutting off two of its corners, Bao Longjun said. “I was furious. My son is innocent. Unlike us rights lawyers and activists, he does not have any political colour. Implicating him like this reminds me of the zhulian system back in imperial China. This is moving further and further away from a civilised society,” Bao Longjun said, referring to the practice of collective family punishment. Detained human rights lawyer, Wang Yu, on Chinese state TV informed of 'failed attempt to smuggle son overseas' This is the third time in three years that Bao Zhuoxuan has tried to flee. In July 2015, the then 16-year-old was detained with his father at Beijing Capital International Airport when he tried to board a flight to Australia to go to high school there. A few hours later, a gang of men burst into their Beijing home and took his mother to an undisclosed location for interrogation, marking the start of the “709 crackdown” in which about 300 rights lawyers and activists were rounded up. Three months later, Bao Zhuoxuan was sent back from Myanmar to Inner Mongolia, where he has spent the last two years living under the constant surveillance of the secret police, according to his father. Wang, a leading figure in China’s burgeoning human rights movement, was charged with subversion of state power, while her husband was accused of the slightly lesser charge of inciting subversion of state power. Wang Quanzhang: the last ‘709’ lawyer left in China’s legal limbo They were released on bail last year and kept under house arrest in Inner Mongolia before moving back to Beijing with their son in August. Bao Longjun said his son had just passed an English proficiency test and was waiting for an offer from the University of Melbourne to study business. The state security authorities in Tianjin told Wang their son would get a new passport, but did not say when. The family was also told not to speak to overseas media, Bao Longjun said. The border control office at the Tianjin airport declined to comment, while police in Inner Mongolia refused to give any details about Bao Zhuoxuan, citing personal privacy.