An activist stood trial in Eastern Court yesterday for kicking a police officer in the knee during a rally marking the second anniversary of riots in Tibet . Designer Derrick Benig, 21, who is also a host on underground radio station FM101, pleaded not guilty to assaulting a police officer outside the central government liaison office early on March 14. Police officer Yuen Wai-tak, who the court heard was kicked while he was squatting in front of Benig to calm him, said his right knee and right thumb were left red and swollen. He was taken to Queen Mary Hospital and a doctor gave him three days' sick leave. Just before 8pm on March 13, 14 protesters gathered outside the liaison office, Yuen said. He asked the crowd who the organiser was and he heard them say: 'We're all organisers.' The group did not apply to the police in advance to protest, he said. Protesters charged towards the police cordon several times - at 8.10pm, 10.30pm, just after midnight and at about 2.50am, the court heard. Just before 3am, Yuen saw Benig being taken away from the rally by two police officers to an area nearby because he was agitated. 'I squatted [in front of him] to tell him to calm down. Then he suddenly looked at me and kicked me once,' Yuen said. The kick was forceful and he was in pain, he said. He then told his colleagues to arrest Benig. Just after midnight, a protester tied a black flag to the liaison office's metal fence but a security guard quickly took it down, he said. Protesters then got a couch and placed it in front of the barricades. A few of them were sitting on it while they ate, smoked and chatted, Yuen said. But they suddenly tried to climb over the barricades by standing on top of the couch. Benig was charged under the Police Ordinance, which provides for a maximum penalty of six months' jail and a fine of HK$5,000. Student activist Christina Chan Hau-man was in court to show her support. The trial continues on Monday before Magistrate Li Kwok-wai.