Former Hong Kong leader Leung Chun-ying on Thursday hit out at a court decision that allowed a top London barrister to defend media tycoon Jimmy Lai Chee-ying and insisted it was ridiculous for someone accused of collusion with foreign forces to be represented by a lawyer from overseas.

Leung, now the vice-chairman of the Chinese People’s Political Consultative Conference and known for his combative stance, said the ruling by the Court of Appeal was also a slap in the face to Hong Kong lawyers.

“Is there anything more ridiculous than this? Lai is not charged with any ordinary offence, but conspiracy to collude with foreign forces and it is unbelievable that this case could be represented by a foreign lawyer,” he wrote on his Facebook page.

“What’s more ridiculous is that the judge says allowing a British lawyer to represent Lai will be ‘beneficial to the development of the national security law’ when dismissing the appeal filed by the Department of Justice. That means we are inviting the Brits to ‘develop’ the national security law for Hong Kong, China.”

He was speaking after the Court of Appeal on Tuesday upheld a ruling by the High Court last month to allow London-based King’s Counsel Tim Owen to join Lai’s legal team on the grounds of “clear public interest”.

Owen’s participation was opposed by the department and the Bar Association, but the latter did not lodge an appeal against the ruling. It is not uncommon for the Bar Association to oppose such applications to protect the interests of city barristers.

“All Hong Kong barristers have been slapped in the face by the appeal court judges,” Leung said.

“The judges have been looking up to foreigners on national security affairs,” he said. “Let’s see what the Hong Kong Bar Association has to say.”

Victor Dawes, the chairman of the Bar Association, said the Bar’s position was outlined at the appeal court hearing and declined to comment further.

The Law Society, another influential legal body in charge of the registration of solicitors, also declined to comment on the ground of ongoing legal proceedings.

But a senior lawyer, who asked to remain anonymous, said Leung’s comment was at odds with Hong Kong’s plan to become an international legal centre.

He added that arrangements to allow foreign professionals to practice in the city was permitted under the Basic Law, the city’s mini-constitution.

“It’s broader than counsel coming. It’s quite fundamental that if you must have an international legal centre, you must have mechanisms in place to let commercial firms have access to US lawyers and British lawyers,” he said, adding that national security cases should not be treated differently.

The lawyer explained the department was also allowed to hire foreign barristers and had attempted to do so in the past.

He added has there not been any problems with national security case defendants being represented by non-Chinese barristers who worked in the city.

The lawyer said that judges had taken an oath under the Basic Law to carry out their duties impartially, including in the Owen decision, although he respected Leung’s freedom to express his views.

The appeal court earlier dismissed an argument by government lawyers that overseas counsel could not furnish judges with new perspectives on the Beijing-imposed law.

The court highlighted that the logical conclusion of the argument would be a general ban on the use of barristers from abroad in national security law cases.

The appeal court court judgment said a flexible and sensible approach had to be taken to reach a decision that was in the public interest, given the high-profile case would affect the development of legal principles on the national security law and sedition offences.

But Leung questioned the need to adopt international judicial standards in handling national security cases and quoted the 20th congress of the Communist Party report, which suggested that the nation should be confident in its system and should not copy foreign models.

Lai, 74, will face trial in front of a three-judge panel in the Court of First Instance next month on charges of conspiracy to collude with foreign forces and conspiracy to publish seditious material.

Prosecutors have accused Lai of conspiracy to encourage foreign sanctions or blockades against the city and mainland Chinese officials through articles published by his now-closed Apple Daily newspaper, as well as through a lobbying group he is alleged to have directed and financed behind the scenes.