Judge Alex Lee Wan-tang ruled that West Kowloon principal magistrate Peter Law Tak-chuen had acted beyond his authority by restricting the media from reporting on Chow's subversion trial and that the court must lift the restrictions upon Chow's application.

"The magistrate's reasoning was totally in opposition to the principles of open justice that govern the exercise of judicial power in the context of restricting access to, or reporting of, court proceedings," Lee wrote in his judgment.

He also said the high court "rejects" the contention by the secretary of justice that lifting reporting restrictions "would frustrate the ultimate aim of doing justice."

According to Chow's application for a judicial review, Law - a national security judge handpicked by the government - denied Chow's application to lift reporting restrictions on pre-trial committal proceedings on April 25.

Law ruled that lifting restrictions would lead to "widespread criticism or even attacks" as entire court proceedings could be reported and deter witnesses from testifying due to "psychological pressure."

A barrister herself, Chow, in her application, said section 87A(2) of the Magistrates Ordinance states that a magistrate "shall" lift reporting restrictions, which Lee agreed "imposes a mandatory duty on the magistrate" to do so.

"The magistrate has no discretion but to lift the reporting restrictions at the instance of the accused," Lee said, adding that a magistrate "should not refuse" the application of an accused unless refusal is "strictly necessary" in the interests of justice.

The landmark national security case involves three former leaders of The Hong Kong Alliance in Support of Patriotic Democratic Movements of China: Tonyee Chow, 37; Albert Ho Chun-yan, 70; and Lee Cheuk-yan, 65.

The alliance organized the city's annual candlelight vigils in remembrance of the 1989 Tiananmen crackdown before it disbanded in September following the arrests of its leaders.

Currently, the media must observe certain restrictions in reporting on national security trial proceedings to protect prosecution witnesses.

Section 9P of the Criminal Procedure Ordinance states that bail proceedings may only contain the defendant's name, charge, name of court and judge, name of counsel, result of bail proceedings, and date and place of adjournment.

These restrictions have been enforced in the ongoing bail proceedings of the 47 democrats facing subversion charges under the national security law.

But Lee's decision to lift restrictions on reporting of preliminary committal hearings will allow reporting of pre-trial hearings in a Hong Kong national security case for the first time.