The first person charged under the national security law in Hong Kong will face a trial without jury, the city's High Court ruled on Thursday, in a landmark decision which marks a departure from the global financial hub's common law traditions.

Police say Tong Ying-kit, carried a sign reading "Liberate Hong Kong, revolution of our times," and drove his motorbike into officers during a protest on July 1, knocking several down on the narrow street before falling over and getting arrested.

It was the first day on which the national security law was in force. The law punishes anything authorities deem as secession, separatism, terrorism and collusion with foreign forces with up to life in prison.