Jimmy Lai and several executives of the now closed Apple Daily newspaper are being prosecuted for "collusion with foreign forces", a violation of the drastic national security law imposed by Beijing punishable by life imprisonment.
After local courts ruled London-based lawyer Tim Owen could represent Mr Lai, Hong Kong Chief Executive John Lee asked China's top legislature to decide whether foreign lawyers can take part in national security cases.
The trial was due to start on Thursday, but was adjourned until December 13 to allow prosecutors to propose a new schedule, pending a response from Beijing.
Defense lawyers also revealed that immigration services in the once semi-autonomous territory had "suspended the extension" of Mr Owen's current work visa without giving a reason.
Mr. Owen, a "king's counsel" - that is to say an eminent British jurist - has already worked in Hong Kong in the context of high-profile cases in particular.
The government had argued in court that letting foreign lawyers litigate national security cases posed a risk because there is no way to ensure the confidentiality of state secrets.
When the Court of Final Appeal ruled against the government on Monday, Chief Executive Mr Lee announced that he would ask China to intervene by publishing an "interpretation" of this law imposed mid-2020 by Beijing to put an end to the pro-democracy movement.
Police stationed outside the Hong Kong High Court on December 1, 2022 © ISAAC LAWRENCE / AFP
It was the first time Hong Kong had invoked the mechanism under the National Security Law, which allows Beijing to have the final say on how the law operates.
Already behind bars for his role in the pro-democracy protests that shook the Chinese territory in 2019, Mr. Lai, 74, is one of the leading figures of this movement.
He faces life in prison.
For years, its Apple Daily tabloid criticized Chinese power before being forced to close in mid-2021 after its funds were frozen and some of its executives, including its founder Jimmy Lai, were arrested.
© 2022 AFP