She had planned to run for the same office but was banned on October 12, 2018, after returning officer Franco Kwok Wai-fun found she had not genuinely changed her previous position of advocating self-determination for Hong Kong, despite her ditching the stance ahead of the polls.

Paul Shieh Wing-tai SC said Lau was not given a chance to respond to the allegations.

The counsel said there was nothing in Lau’s oath-taking case, Article 104 or its interpretation that contemplated the scenario of a by-election and could explain why she was disqualified from this particular office defined by constituency.

He questioned why his client was barred from the by-election when Kwok allowed Edward Yiu Chung-yim of the same camp to run in Kowloon West constituency in the March 2018 by-election. Yiu had been similarly stripped of his functional constituency seat over improper oath-taking.

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This suggested Lau could stand in another constituency if Kwok was correct.

“It is only for Kowloon West, for some reason, that she just can’t stand,” Shieh continued. “There is no rational reason. No election-related reason has been given as to why this distinction was drawn.”

Shieh also observed that Yiu was asked to explain his statements, which raised a “gigantic question mark as to why it had not been done in this case”.

Kwok’s counsel, Johnny Mok Shu-luen SC, said Lau’s case was unlike the previous petitions successfully lodged by opposition activists Agnes Chow Ting or Ventus Lau Wing-hong because she had been disqualified by a court before.

Chan’s counsel, Mike Lui, agreed that the oath-taking incident must be relevant.

“This is indeed a very distinctive feature of this case,” Lui said.

Mok argued that the finding of the court suggested Lau “lacked the requisite qualities to stand for office” and the absence of these qualities would continue until “a material change” occurred.

“The lingering effect is lost when the earlier court finding is superseded by a fresh determination based on evidence the person is now in possession of the requisite qualifications,” Mok continued. “Failing such determination, the previous finding continues to have an effect.”

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Mok further argued that both the court and the returning officer could make such a determination, but ultimately it was a constitutional question for a judge.

“The person can repent,” he continued. “If she can tell the judge what amounts to repentance, the court can judge.”

“But no question was asked,” Chow observed.

To this, Mok replied: “Your lordship may be minded to find not giving her an opportunity to respond may amount to an irregularity in the election process.”

The court has reserved judgment.