The High Court has been asked to review the constitutionality of an amendment to the legislature’s rule book that was pushed through by the pro-government camp to thwart the filibustering tactics of the opposition. Opening the two-day hearing on Wednesday, Hectar Pun Hei SC argued that the new rule to lower the quorum for certain debates of government bills was unconstitutional. Pun, who is counsel for disqualified lawmaker “Long Hair” Leung Kwok-hung, said the amendments to the Legislative Council’s rules of procedure secured by the pro-establishment bloc on December 15, 2017, should be declared void and of no effect because they are inconsistent with the Basic Law , the city’s mini-constitution. His argument was also supported by former civil servant Kwok Cheuk-kin, known as the “king of judicial review”, who filed a similar application that lowering the quorum from 35 to 20 members was against Article 75 of the Basic Law. But Benjamin Yu SC, arguing for the Legislative Council president, countered that it was clear that the same Article 75 empowered the legislature to decide its own procedures based on its needs at the time, which in this case was to address concerns about filibustering. The hearing centres on a crucial change to the council’s rule book that reined in the pan-democrats’ frequent tactic of calling for quorum counts to grind proceedings to a halt so as to block bills or motions they deemed inappropriate. Pan-democratic lawmakers had opposed the controversial rule, raising questions of constitutionality – but their power was significantly weakened by two separate court rulings that removed six of their members, including Leung, for improper oaths of office . Legco approves rule book changes after dramatic debate with 11 pan-dems booted out of chamber Now the court must decide on the meaning of “Legislative Council” in Article 75, which stipulates that “the quorum for the meeting of the Legislative Council … shall be not less than one half of all its members”. The same article states “the rules of procedure of the Legislative Council shall be made by the council … provided that they do now contravene this law.” Pun argued that the drafters of the Basic Law clearly intended for this quorum requirement to apply to both the plenary council and the council sitting in committee – also known as a committee of the whole council – when it considers a bill clause-by-clause before the voting. He said that was because the two councils share the same membership, follow the same voting procedures and rules of speaking – with the exception that members may speak more than once when discussing details of the bill – and undergo the same process of making amendments integral to the legislative process. His argument was in line with independent legal advice obtained by the Legco president in 2014 and 2017. But Yu pointed out that the two councils were also different in constitutional status, with the committee of the whole council being an ad hoc body created by the legislature under the rules of procedure. “My learned friend couldn’t really give a good explanation why the Basic Law as a constitutional instrument would be concerned with quorum – unless it was concerned with the very body that was created as an important part of the political structure of the Hong Kong Special Administrative Region,” Yu said. “At the end of the day it’s the [plenary] council which passes the bill.” Showdown in Legco over changes to its rule book: What’s fuelling the continuing clash? Wong Yan-lung SC, a former justice secretary representing the incumbent minister, will respond on Thursday when the hearing continues before Mr Justice Anderson Chow Ka-ming. Leung was booted from the legislature when the High Court declared in July 2017 that he had taken an invalid oath when he displayed props and chanted slogans during his swearing-in ceremony on October 12, 2016. He has applied for leave to bring his case to the Court of Final Appeal, but judges have yet to reach a decision.