Three core members of a now-disbanded alliance behind Hong Kong’s Tiananmen Square vigil were each jailed for four and a half months for refusing to assist police in an investigation into the group’s alleged breaches of the national security law.

The trio from the Hong Kong Alliance in Support of Patriotic Democratic Movements of China returned to West Kowloon Court on Saturday to be sentenced by a magistrate approved by the city’s leader to hear the case.

The group’s former vice-chairwoman Chow Hang-tung, and ex-standing committee members Tsui Hon-kwong and Tang Ngok-kwan, were convicted earlier this month under the implementation rules of the Beijing-imposed law.

Attendees hold up candles at the Tiananmen Square vigil in 2019.

Simon Leung Kam-wai and Chan To-wai, also former standing committee members, earlier pleaded guilty and served a three-month sentence.

Principal Magistrate Peter Law Tak-chuen said immediate imprisonment was required given the nature of the offence and level of premeditation seen in the defendants’ “total refusal” to assist police.

“Sentencing for offences relating to national security must reflect the nation’s determination to maintain national security and send a clear message to society that the law does not condone any violation,” he said.

Immediately after Saturday’s ruling, Tsui and Tang were released on bail pending a High Court appeal.

Chow, who also secured bail on the same terms pending an appeal, indicated she would not sign the relevant paperwork as she did not accept some of the conditions. She will remain in the maximum security Tai Lam Centre for Women, where she is also remanded pending a separate High Court trial related to the alliance.

Speaking before sentencing, Chow argued the “degrading” label of foreign agent was placed on the alliance to force its members into submission.

“When the nation’s interest is defined by one party, or indeed, one person, so-called national security would inevitably become a threat to people’s rights and security, as demonstrated by Tiananmen, by Xinjiang, and indeed Hong Kong,” she said.

The magistrate brushed aside Chow’s speech, saying “I just want to deal with the legal proceedings in a pure, legal sense”.

The alliance’s ex-standing committee member Tsui Hon-kwong.

But Chow countered that her prosecution was spurred by political motives and the court’s attitude was in effect “ignoring reality”.

Senior Counsel Philip Dykes, in pleading for leniency for the other two accused, complained that his job was hindered by prosecutors withholding information about the alleged foreign entities, which prevented him from assessing the strength of the evidence and the impact of the non-compliance concerned.

The implementation rules require a suspected foreign agent, or one with links to Taiwan, to surrender information about its operation at police’s request.

The defence expressed at one point during the proceedings that the requirement ran contrary to the common law protection against self-incrimination, but later said it acknowledged the protocol was not amenable to judicial challenge under the new legal regime.

The trio maintained in last year’s trial that the alliance was not a foreign agent and thus had no obligation to cooperate, but the court found “reasonable grounds” to believe otherwise, saying the group had “close” interactions with local and overseas organisations that shared “common objectives”.

A redacted police report submitted to the court highlighted the alliance’s alleged connections with six unspecified groups and Mark Simon, the long-time top aide of jailed media tycoon Jimmy Lai Chee-ying, as evidence of the former being a foreign agent. Chow said the alliance had no ties with the groups concerned.

The report also claimed that the request for information was necessary to prevent and investigate “possible” national security violations by the alliance, including secession, subversion, collusion with foreign forces and related incitement and conspiracy offences.

The alliance’s ex-standing committee member Tang Ngok-kwan arriving at West Kowloon court in 2022.

The alliance’s goal to “end one-party dictatorship”, one of its five operational objectives, may amount to a subversion offence, according to the report.

The group had held a candlelight vigil in Causeway Bay’s Victoria Park since 1990 to mark the military crackdown on the democratic movement in Beijing a year earlier.

The annual event had been the only large-scale commemoration on Chinese soil to remember the 1989 crackdown.

Police prohibited the vigil for the first time in 2020 on public health grounds related to the Covid-19 pandemic. The 2021 event was banned for similar reasons, before the alliance’s dissolution in September that year.

A packed Victoria Park for the Tiananmen Square vigil in 2019

The redacted police report claimed that the vigil and other activities held relating to the “Tiananmen incident” were intended to provoke public hatred towards authorities in an effort to revive the 1989 movement and overthrow the Chinese government.

Chow, along with the alliance, its former chairman Lee Cheuk-yan and vice-chairman Albert Ho Chun-yan, are awaiting a separate High Court trial for allegedly inciting subversion of state power under the national security law. They face up to 10 years in prison if convicted.

Lee is currently remanded in the maximum security Stanley Prison. Ho has been released on bail.