Mr Lai, one of Hong Kong's best-known pro-democracy activists, has been behind bars since late 2020 and charged with "colluding with foreign forces", a crime under the national security law. This law was promulgated in 2020 in the wake of the protests that shook the territory from June to December 2019.
To ensure his defense, the founder of Apple Daily, a newspaper critical of the Chinese government forced to close in 2021, had appealed to the British lawyer Tim Owen, specialized in the defense of human rights. Mr. Owen's appointment was initially endorsed by the magistrates, against the advice of the authorities.
But Beijing intervened in December to give Hong Kong Chief Executive John Lee the power to ban foreign lawyers from litigating national security cases in the metropolis.
In the aftermath, the National Security Committee, a body directly under Beijing's orders, asked the immigration authorities to withdraw the British lawyer's work visa.
In his ruling on Friday, Magistrate Jeremy Poon said the tycoon could not challenge a decision of the committee in court.
"The courts (of Hong Kong) have no jurisdiction over the work" of the National Security Committee, he wrote in his ruling.
"The supervisory power (of the committee) is the exclusive responsibility" of Beijing, he added.
Mr Lai's trial, which was due to start in December 2022, was postponed to September 2023 after Hong Kong asked Beijing to prevent Mr Lai from being represented by Tim Owen.
On Tuesday, Reporters Without Borders (RSF) and a hundred international media leaders called for the "immediate release" of Jimmy Lai.
Hong Kong is ranked 140th out of 180 countries in RSF's 2023 World Press Freedom Index, after falling 122 places "in just 20 years", according to the NGO. China ranks 179th.
© 2023 AFP