“A foreign country has no right to interfere with the way in which Hong Kong strives to preserve its core values of rule of law and law and order,” said Mr Justice Alex Lee Wan-tang, who was joined by madam justices Esther Toh Lye-ping and Susana D’Almada Remedios.

“If sanctions are imposed or proposed by a foreign country with a view to influencing the internal affairs of Hong Kong, then mutual respect which is the very foundation of ‘comity’ is not there, not because of any ‘investigation’ or determination of this court, but by the act of the foreign country.”

The ruling delivered at West Kowloon Court followed a dispute on whether to admit evidence of prosecution witness Professor Wang Guiguo, as the trial entered its 10th day.

Wang is chair professor of Chinese and comparative law at City University and the husband of pro-establishment lawmaker Priscilla Leung Mei-fun, who also sits on the Basic Law Committee.

The prosecution has sought to rely on Wang’s testimony to show the legal effects of various pieces of US legislation on the city, including the 2019 Hong Kong Human Rights and Democracy Act and the Hong Kong Autonomy Act in 2020, which were enacted in response to the city’s anti-government protests and Beijing’s imposition of the national security law.

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The professor concluded the 2019 act had a “severe” impact on the stability of Hong Kong as an international financial hub, the court heard.

Lai’s counsel, Steven Kwan Man-wai, argued Wang’s evidence was irrelevant to determining if the tycoon was guilty under the national security law.

He said whether the US legislation in question amounted to “sanctions, blockade or other hostile activities” was a matter the court could decide on its own without a foreign law scholar’s help.

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He stressed the prosecution did not rely on the professor’s evidence to establish any causal link between Lai’s alleged requests and the sanctions imposed by the West.

Prosecutor Anthony Chau Tin-hang highlighted the “extensive” references made to US sanctions by Lai’s associates in various messaging records to show the professor’s evidence had probative value.

In their ruling, the judges noted Wang’s opinion might provide “some circumstantial support” to the prosecution’s case about the existence and scope of the conspiracies Lai allegedly orchestrated.

They considered the professor’s evidence to be useful in helping the court determine whether the actions taken by the United States could be deemed as hostile conduct for a foreign collusion offence.

Toh also said in her additional remarks that the three judges were not bound to accept Wang’s evidence as “Bible” truth.

“We must also emphasise that he is a witness, and as judges of facts, we have the ultimate decision to make, that is whether we accept all or any part of the evidence,” she said.

The first prosecution witness, former Apple Daily publisher Cheung Kim-hung, is expected to take the stand on Wednesday.

Prosecutors slapped the 76-year-old Apple Daily founder with two conspiracy charges of collusion with foreign forces under the national security law and a third conspiracy charge by invoking colonial-era sedition legislation.

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They earlier alleged Lai had exercised full control over his now-defunct tabloid and given instructions to its senior editorial staff when it published 161 seditious articles between April 2019 and June 2021, 31 of which were said to have also called for foreign sanctions after the national security law took effect.

Lai was also said to have financed and orchestrated an international lobbying campaign titled “Fight for Freedom, Stand with Hong Kong” in a bid to convince the US and its allies to introduce sanctions and trade restrictions, as well as sever agreements with Hong Kong concerning the extradition of fugitives and mutual legal help.