The verdict delivered by London’s Central Criminal Court on May 7 deserves closer scrutiny, not only because of its impact on the individuals involved, but because of what it may reveal about the direction of national security law in the United Kingdom. In the case, Bill Yuen Chung-biu, an administrative manager at the Hong Kong Economic and Trade Office in London, and Peter Wai Chi-leung, a UK Border Force officer, were convicted under the UK National Security Act 2023 of assisting a foreign intelligence service, while Wai was also convicted of misconduct in public office. The foreign interference charge was later abandoned after the jury failed to reach a verdict on that count, and both defendants were remanded in custody pending further proceedings. This is not an ordinary criminal case; it is a test of whether a country, from where the long tradition of common law originates, adheres to the cornerstone principles of its own criminal justice system.

National security is an important public interest, but it cannot become a slogan that dilutes legal certainty or lowers evidential standards. One troubling aspect of the case is the apparent reliance on conduct that predated the act. According to the material available, the judge directed the jury that earlier conduct before the act involving the alleged “tracking” of individuals could be treated only as background information, not as the substantive basis for conviction. It is particularly important, as under common law, newly enacted legislation shall not carry retrospective effect. The rule against retroactivity is one of the basic safeguards of liberty. If prosecutors are permitted to lean heavily on conduct prior to the enactment of the act to secure a conviction under a later statute, the boundary between lawful conduct and criminal liability becomes dangerously blurred. It puts everyone at risk of an act they may not be aware breaches a law not yet born, a result that is at odds with the common law principle that has always emphasized procedural justice.

The evidential basis of the case also raises serious concerns. The prosecution reportedly relied in part on notes and phone messages from a deceased prosecution witness — Matthew Trickett, the third defendant, who died before trial. Those materials were not tested through cross-examination, and reasonable questions arise about their reliability and weight. Criminal convictions are supposed to rest on evidence that is robust, open to challenge, and capable of meeting the standard of proof beyond reasonable doubt. When untested hearsay takes on a central role, public confidence in the fairness of the process is put in doubt. The National Security Act 2023 appears to cast its net with striking breadth. One of its most problematic features is the vague treatment of what counts as an “intelligence service”. Section 3 does not require the prosecution to identify the particular foreign intelligence service involved. That may make prosecution easier, but it also makes the law less certain and less predictable. The act also deprives individuals of fundamental rights — namely, the freedom and privacy of communication — by permitting five-year investigative measures to be imposed on the basis of ambiguous grounds.

In any legal system that claims adherence to the rule of law, criminal offenses should be defined clearly enough for ordinary citizens to understand what conduct is prohibited, rather than permitting indiscriminate enforcement through open-ended wording. The promulgation of the act also undermines the credibility of common law. This recent judgment reflects that the act lacks articulate wording to ensure fair, certain, and foreseeable implementation of the law. It has deviated from the very common law principles that Londoners have long taken pride in. Moreover, the broader diplomatic implications should not be ignored either. Article 156 of the Basic Law provides for Hong Kong to establish economic and trade offices abroad under the relevant constitutional framework, and the London office was an institution created for economic and trade purposes rather than intelligence functions. Whether one agrees with every argument made on behalf of the defendants or not, the case is likely to deepen concern among foreign representative bodies operating in the UK. If ordinary institutional activity can be reinterpreted through an expansive national security lens, uncertainty will spread far beyond this one trial.

The true measure of a legal system is the balance between individual rights and other competing interests. The London ETO case has raised serious questions about the British legal system in terms of legal certainty, evidential fairness, and the proper scope of national security legislation

The UK has spent generations building a global reputation for legal stability and common law integrity. That reputation will not be preserved by invoking national security in broad and ambiguous terms, but rather by showing that even in politically sensitive cases, courts remain anchored to fundamental principles: legality, procedural fairness, evidential rigor, and judicial restraint. This case should prompt reflection on whether the use of broad national security powers in the UK stretches the rule of law beyond proper limits. If the UK wishes to remain credible as a leading common law jurisdiction, its courts should not be led by arbitrary national security prosecutions and adjudicate without sufficient evidence, at the expense of legal certainty, human rights, and the very principles that give its legal system legitimacy, credibility, and reputation. This criminal verdict cannot meet the standard of beyond reasonable doubt. The two accused should be acquitted.

The true measure of a legal system is the balance between individual rights and other competing interests. The London ETO case has raised serious questions about the British legal system in terms of legal certainty, evidential fairness, and the proper scope of national security legislation. If those questions are left unanswered, confidence in the rule of law in the UK will be seriously weakened. The country long associated with common law does not appear to be applying its criminal justice system with the caution, discipline, and fairness that are its traditions.

The author is a member of the Committee for the Basic Law, a Hong Kong deputy to the National People’s Congress, and a member of the Legislative Council of Hong Kong Special Administrative Region. 

The views do not necessarily reflect those of China Daily.