Three former leaders of a disbanded group that organized vigils marking Beijing's 1989 Tiananmen Square crackdown on pro-democracy protests went on trial in Hong Kong on Thursday, half a decade after their 2021 detention. 

The annual memorial event was once legal in China-ruled Hong Kong, and celebrated as a symbol of the relative freedom there. But it was stamped out in the aftermath of the COVID pandemic using a new national security law imposed from Beijing.

Police guarded the West Kowloon Magistrates' Court on Thursday amid considerable public and press interest in the case. 

Who is on trial and how did they plead? 

Lee Cheuk-yan, 68, Albert Ho, 74, and Chow Hang-tung, 40, are three former leaders of the Hong Kong Alliance in Support of Patriotic Democratic Movements of China.

This group was founded in 1989, when Hong Kong was a British territory, to show solidarity with student-led pro-democracy protests on mainland China. 

These came to a head with the June 4 crackdown in Beijing's Tiananmen Square later that year, an event whose history is suppressed in China, and the group later began to commemorate the deaths. 

The trio are accused of "incitement to subversion," which can carry a jail term of up to 10 years. 

Prosecutors focused on Thursday on laying out their case against Ho, who pleaded guilty and requested a reduced sentence. 

Ho pleaded guilty to a summary read by prosecutor Ned Lai that said "ending one-party rule" referred to putting an end to the leadership of the Chinese Communist Party. This would be in violation of the constitution as there was no legal means to end it, the prosecution said.

Former trade union leader Lee and Chow, a barrister and University of Cambridge graduate who was granted permission to represent herself, both pleaded not guilty. 

The three defendents are being judged by a trio of judges handpicked by Hong Kong's Chief Executive John Lee Ka-chiu, not a jury. 

On Friday, Chow said the Hong Kong Alliance was not pushing for an end to Communist rule, but rather for more democraticization in Hong Kong.  

How Hong Kong stamped out Tiananmen Square memorials, after 2020's last hurrah

The annual Tiananmen vigils, which used to attract thousands, were outlawed in 2020 under restrictions imposed due to the COVID pandemic.

Despite the ban, thousands turned out for a candlelight vigil on June 4 that year. Further public protests followed once COVID restrictions to assembly were loosened.

However, the Hong Kong Alliance in Support of Patriotic Democratic Movements of China was outlawed and disbanded by 2021, with leading figures arrested. Vigils have since been outlawed and security ramped up, although some sites with less reason to fear prosecution like the US Consulate have continued to light candles in a nod to the ceremonies.

Several monuments to June 4, such as the "pillar of shame" have also been removed from the cities' universities in recent years. 

"This case is not about national security – it is about rewriting history and punishing those who refuse to forget the victims of the Tiananmen crackdown," said Sarah Brooks, the Asia deputy director of rights group Amnesty International.

Beijing says Hong Kong's national security law ⁠was necessary to restore order after the sometimes violent protests of 2019. Beijing imposed the law directly, bypassing Hong Kong's own legislature, amid doubts that it would win approval from the city's own representatives.

Edited by: Darko Janjevic