He said the ruling was “legally indefensible” and “symptomatic of a growing malaise in the Hong Kong judiciary”.

He did not stop with that piece. Sumption went on to tell the BBC the verdict was “a major indication of the lengths to which some judges are prepared to go to ensure that Beijing’s campaign against those who have supported democracy succeeds”.

Other overseas judges have been more optimistic that their presence “might moderate the persecutory zeal of the authorities”, but Sumption insisted he saw no useful purpose in remaining.

His scathing remarks drew a 2,900-word rebuttal from the Hong Kong government, which disagreed strongly that the courts came under political pressure and criticised him for unfair comment on the work of the city’s judges while choosing to “abandon them”.

The episode also raised questions about Hong Kong’s system of inviting eminent foreigners from other common law jurisdictions to join a select group of non-permanent judges who sit in the city’s top court.

Cases that go to the Court of Final Appeal are heard by a five-member panel made up of the chief justice, three permanent judges and an overseas judge since Hong Kong returned to Chinese rule in 1997.

The non-permanent justices are paid the same as their permanent counterparts on a pro-rata basis. Top judges are paid HK$399,950 (US$51,200) a month.

Overseas judges are also entitled to first class flights to and from Hong Kong, with an accompanying spouse if their stint is to be longer than 29 days.

The judiciary said they were also put up in a hotel and travel by official transport.

But the perks do not appear enough to retain overseas judges, whose numbers have gone down from 15 in June 2020 to eight at present.

Former UK Supreme Court judge Lawrence Collins, 83, who resigned at the same time as Sumption, said he was leaving “because of the political situation in Hong Kong”.

But he added that he had “the fullest confidence in the court and the total independence of its members”.

Former Canadian chief justice Beverley McLachlin, 80, has said since then she will retire from her Hong Kong position on July 29, after completion of her second three-year term.

Her departure will leave seven overseas judges in the pool, from the UK, Australia and New Zealand. There are also four non-permanent city judges.

‘Very unfair to remaining judges’

The Hong Kong government was not alone in giving a barbed response to Sumption’s views.

Anthony Rogers, a former senior vice-president of the city’s Court of Appeal, wrote to the Financial Times, criticising Sumption’s article for breaching the principle of not commenting on ongoing cases, especially when he was more senior than the judges who might hear any appeals.

He was apparently referring to the Department of Justice’s decision to appeal against the High Court acquittal of former district councillor and lawyer Lawrence Lau Wai-chung. Rogers declined to comment further.

Ronny Tong Ka-wah, a lawyer and member of the government’s key decision-making body, the Executive Council, said he was disappointed that Sumption violated “the most basic” requirement for judges to avoid commenting on politics.

“It was very unfair to the [overseas non-permanent] justices staying in office, as he implied they were staying only because they received money from the Communist Party and instructions from Beijing,” he said in a television interview. “How can you say such a thing, unless you have some very strong evidence?”

Beijing has not sat on the sidelines of the row either.

The Hong Kong and Macau Affairs Office’s social media account posted two commentaries within three days under the pen name of “Gang Ao Ping”, which attacked Sumption for “dishonesty, untrustworthiness and lack of integrity”.

The liaison office, national security office and the foreign ministry’s office in Hong Kong all issued statements in defence of the city’s rule of law and said Sumption’s remarks were part of attacks mounted by “external forces”.

Veteran political scientist Lau Siu-kai, a consultant for semi-official Beijing think tank the Chinese Association of Hong Kong and Macau Studies, said Sumption was a “treacherous person with a sinister motive”.

He said Beijing could not accept that a departing foreign judge would use the occasion to hurt a place that had given him so much trust and respect.

“The Sumption incident must have confirmed Beijing’s fears that external hostile forces are using foreign judges to smear Hong Kong’s reputation,” Lau told the Post.

“Beijing is politically prepared for a Court of Final Appeal without foreign judges and will easily take it … however, it will not stop Hong Kong from appointing foreign judges. Beijing will take whatever happens in its stride.”

Tong wrote an op-ed published by the Post after Sumption resigned where he accused the British government of pressuring UK judges to quit their positions on the Court of Final Appeal.

He also questioned the need for foreign justices in the top court and said Hong Kong’s senior judges were already worthy of international respect.

But he clarified later that any change to the system should not be considered lightly while Hong Kong was “under attack”.

Chief Executive John Lee Ka-chiu made it clear on June 18 that foreign judges would continue to hear cases in the Court of Final Appeal.

Lee also told the Post in a later interview that the city would maintain the practice to show the world its transparency.

“I think we shouldn’t be affected by one or two individuals’ behaviour or their own perspective of things,” he said.

The head of the Chinese foreign ministry’s office in Hong Kong, Cui Jianchun, told reporters on the sidelines of an event that the inclusion of foreign judges could be revisited if the system no longer served the city’s “one country, two systems” governing principle.

But lawmaker Priscilla Leung Mei-fun, a member of the powerful Basic Law Committee that advises the central government on the city’s mini-constitution, played down the fallout from Sumption’s departure.

She backed the presence of non-permanent foreign judges and said that even a retired judge from the city might bad-mouth the legal system in “such a tense international environment”.

“We should manage the risks but not reject the system altogether,” she said. “The most important thing is to find the right people.”

She suggested the recruitment of foreign judges from a wider range of jurisdictions, but added that “we also shouldn’t assume that all people from the UK act this way”.

Non-permanent overseas judges have come from the UK, Canada, Australia and New Zealand. Leung suggested including judges from places such as Singapore, Malaysia and India.

Chinese University law professor Stuart Hargreaves said there was no question that Hong Kong had sufficient numbers of highly skilled judges, but that was not the only consideration when deciding whether to continue having foreigners as non-permanent justices.

“In the current geopolitical environment, abandoning the practice now could be interpreted overseas as Hong Kong beginning to decouple itself from the common law world and I don’t think that would serve Hong Kong or China’s interests,” he said.

Hargreaves added some foreign judges might hesitate to accept Hong Kong’s invitation if they felt they might be “subject to state-level criticism”, but others would still be attracted by what was a prestigious role at a globally respected legal institution.

“But I would not at all be surprised to see potential candidates drawn from a more diverse range of common law jurisdictions, and for the overall prominence of the overseas judges on the court to continue to decline,” he added.

Hargreaves, who analysed Court of Final Appeal judgments between 2011 and 2019, observed that the contributions of overseas justices had diminished in recent years.

‘Not essential, but desirable’

The option for Hong Kong courts to recruit judges from other common law jurisdictions is provided by Article 92 of the Basic Law, Hong Kong’s mini-constitution.

Article 82 also rules that the Court of Final Appeal may invite judges from other common law jurisdictions to sit on its bench. The law provides a cap of 30 for all non-permanent judges, including those from the city.

The article was carried over almost entirely from an annex to the 1984 Sino-British Joint Declaration drawn up before the 1997 handover, under a section relating to apex court rulings.

The inclusion of non-permanent foreign judges in the top court was questioned during the drafting of the Basic Law in the late 1980s.

One opinion said it would be “intolerable to have foreigners trying Chinese citizens on Chinese soil”.

Hong Kong has appointed 30 overseas non-permanent judges since 1997. Eight continue to serve and about half of the other 22 served two or three three-year terms.

Sumption had been with the Court of Final Appeal for five years before his resignation.

British judge Leonard Hubert Hoffmann, one of the seven remaining non-permanent judges, was appointed in 1998 and is the longest serving foreign judge. Three others have sat on the Hong Kong bench for more than 10 years.

The judiciary said non-permanent judges would be appointed when suitable candidates were identified and were prepared to serve on the Court of Final Appeal.

The two overseas non-permanent judges appointed after the 2020 national security law came into force were both from Australia. Justices Patrick Keane and James Allsop told the Post they intended to remain with the court.

Domestic criticism of the foreign judge system has persisted over the years, and some have argued that foreign judges were ignorant of city laws and circumstances.

Others questioned their “divided patriotic ties”.

Professor Simon Young Ngai-man of the University of Hong Kong’s law faculty referred to such negative views in an essay published in The Cambridge Handbook of Foreign Judges on Domestic Courts last year.

He argued that the contribution of foreign judges lay in the “wisdom, authority and diversity” they brought to decision-making in the top court’s cases.

“The Hong Kong judges are now the driving force in most jurisprudential developments, but I have no doubt having the non-permanent judges adds something more in each case, and in some cases might well make a difference,” he told the Post.

Hong Kong’s two legal professional groups said they wanted the system to stay.

The Law Society of Hong Kong said it strongly supported keeping the overseas non-permanent judges because of their significant contributions.

Hong Kong Bar Association chairman Victor Dawes said the overseas judges had enriched Hong Kong’s jurisprudence and played an important role in maintaining the city’s status as an international dispute resolution centre.

Johnny Mok Shiu-luen SC, also a member of the Basic Law Committee, said it might not be essential to have overseas judges in the Court of Final Appeal, but it was desirable in preserving the city’s 180-year-old common law tradition.

“This is our greatest legacy and a very important one, affecting not only our judicial system but also a spirit and a tacit understanding that underpins the operation of the entire society,” he said.

“If we want to maintain a tradition, we must continue to optimise it by bringing in heavyweight practitioners to make contributions within our system. [Overseas] judges are making such contributions.”

Mok appealed to sceptics not to make too much of the row over Sumption’s views.

“He has uttered a few words and done a few interviews – so what? In the long run, they won’t affect anything,” he said.

Political observer Johnny Lau Yui-siu said Beijing wanted to maintain the status quo mostly because the presence of foreign judges helped consolidate Hong Kong’s legal prestige on the international stage.

But he added that the situation was developing and not entirely under Beijing’s control.

“As current judges quit and do not renew their terms, the only way is to appoint new judges,” Lau said. “Will there be people joining? Will the newcomers’ prestige not be high enough?

“In the eyes of Beijing, this is a time of observation.”