The increasing use of live facial recognition (LFR) technology by police forces in the United Kingdom has sparked considerable debate. LFR systems scan faces in public spaces in real-time, comparing them against a ‘watchlist’ of individuals. When a potential match is found, an alert is generated for police officers to investigate. While proponents argue that LFR is a valuable tool for preventing and solving crime, critics raise significant concerns about its impact on privacy, human rights, and the potential for error and discrimination. This landscape brings a crucial question for the justice system to the fore: should evidence derived from LFR be admissible in criminal proceedings in the absence of a specific law passed by Parliament to govern its use? This essay will argue that LFR evidence should not be admissible without a dedicated statutory framework. The current legal position, which relies on general rules of evidence and broad police powers, is inadequate to address the unique and intrusive nature of this technology. A specific statute is necessary to provide legal certainty, ensure compliance with human rights, and maintain public trust in the justice system.
The Current Approach to Admissibility
In England and Wales, the admissibility of evidence in criminal trials is primarily governed by the principle of relevance. Evidence is admissible if it is relevant to a matter in issue, and it is generally not excluded, even if it has been obtained improperly. However, this general rule is subject to important judicial discretions designed to ensure a fair trial. The main source of this discretion is found in section 78 of the Police and Criminal Evidence Act 1984 (PACE). Section 78(1) states that a court may refuse to allow evidence on which the prosecution proposes to rely if it appears to the court that, “having regard to all the circumstances, including the circumstances in which the evidence was obtained, the admission of the evidence would have such an adverse effect on the fairness of the proceedings that the court ought not to admit it.”
Under this framework, evidence obtained from LFR would be considered relevant if it tends to prove or disprove the identity of a person involved in a crime. Its admissibility would then depend on a challenge under section 78. A defence team could argue that the use of LFR to identify their client was so unfair or improper that admitting the evidence would compromise the fairness of the entire trial. The judge would need to perform a balancing act, weighing the public interest in prosecuting crime against the defendant’s right to a fair trial under Article 6 of the European Convention on Human Rights (ECHR). In making this decision, a court would consider factors such as the reliability of the LFR technology, the way it was deployed, and whether its use breached other fundamental rights, such as the right to a private life under Article 8 ECHR. This case-by-case approach, however, leaves significant uncertainty and places a heavy burden on individual defendants to challenge a state-sanctioned technology.
The Judgment in *R (Bridges) v Chief Constable of South Wales Police*
The legal vacuum in which LFR operates was brought into sharp focus by the landmark Court of Appeal case of *R (Bridges) v Chief Constable of South Wales Police* (2020). Mr Bridges, a civil liberties campaigner, challenged the legality of the use of LFR by South Wales Police. Although his initial claim in the High Court was dismissed, the Court of Appeal found in his favour, ruling that the force’s use of the technology was unlawful on three grounds.
First, the court held that the deployment of LFR was not “in accordance with the law” as required by Article 8(2) ECHR, which protects the right to respect for private and family life. For an interference with this right to be lawful, there must be a basis for it in domestic law that is accessible and foreseeable. The Court of Appeal found that the existing legal framework, which consisted of generic police common law powers and vague policy documents, lacked the necessary precision. It gave the police too much discretion over who could be placed on a watchlist and where LFR could be deployed (Bridges, 2020, para 98). This lack of clear rules failed to provide the public with adequate protection against arbitrary interference with their Article 8 rights.
Second, the court found that the police force had failed to comply with its data protection obligations under the Data Protection Act 2018 by not conducting an adequate Data Protection Impact Assessment (DPIA). The assessment failed to properly consider the risks to the rights and freedoms of individuals. Finally, the court concluded that the police had not fulfilled their Public Sector Equality Duty (PSED) under the Equality Act 2010. They had not taken sufficient steps to investigate whether the LFR software had a racial or gender bias, which could lead to a disproportionate number of false positive matches for women and people from Black, Asian and Minority Ethnic (BAME) backgrounds.
While the *Bridges* case concerned the legality of the deployment of LFR, not the admissibility of evidence derived from it, its implications are profound. If the very act of gathering evidence using LFR is found to be unlawful because it violates Article 8, a defendant has a powerful argument under section 78 of PACE that admitting such evidence would be unfair. A judge would have to seriously consider whether to admit evidence obtained through a process that the Court of Appeal has declared “not in accordance with the law.” The ruling demonstrates that the current non-statutory framework is legally deficient, and relying on it to ground the admissibility of evidence is therefore highly problematic.
The Case Against Admissibility Without a Statute
There are several strong arguments for why LFR evidence should not be admissible until Parliament enacts a specific statutory framework. The primary concerns relate to human rights, the fairness of legal proceedings, and the lack of democratic oversight.
The most significant objection is the infringement of the right to privacy under Article 8 ECHR. LFR technology does not just target suspected criminals; it captures and processes the biometric data of every person who passes before the camera. As the Information Commissioner’s Office has noted, this turns public spaces into areas where citizens are subject to constant identity checks (ICO, 2019). The *Bridges* judgment confirmed that the current generic legal framework is insufficient to justify this substantial interference with privacy. A bespoke statute could provide the necessary clear and foreseeable rules required by Article 8(2), setting out strict criteria for when, where, and for what purpose LFR can be deployed. Without such a law, there is a risk that evidence submitted to court has been obtained through a mass surveillance practice that is fundamentally unlawful.
Furthermore, there are serious concerns regarding the right to a fair trial under Article 6 ECHR, which is the cornerstone of the s.78 PACE discretion. The reliability of LFR technology is a key issue. Studies have shown that LFR systems can have high error rates, particularly for women and ethnic minorities (NIST, 2019). Admitting evidence from a potentially biased algorithm risks causing a miscarriage of justice. A bespoke statute could mandate independent testing and set minimum accuracy thresholds that LFR systems must meet before their outputs can be used as evidence. Additionally, the ‘black box’ nature of many commercial LFR algorithms presents a challenge for the defence. If the inner workings of the software are a trade secret, it becomes almost impossible for a defendant to meaningfully scrutinise and challenge the evidence, undermining the principle of equality of arms central to a fair trial. A statute could create clear disclosure duties, compelling the prosecution to provide the defence with sufficient information about the system’s operation and error rates.
Finally, the introduction of a technology as powerful and controversial as LFR should be subject to full parliamentary debate and democratic consent. Allowing police forces to adopt and use LFR under broad common law powers bypasses this crucial democratic process. Professor Marion Oswald has argued that such a “significant and intrusive capability” requires a “clear and specific legal basis” and should not be introduced by stealth (House of Commons Science and Technology Committee, 2019). A parliamentary statute would ensure that society as a whole, through its elected representatives, can weigh the benefits of LFR against its societal costs and establish a clear and democratically legitimate framework for its use.
Arguments for Retaining the Current Framework
Despite the significant concerns, some may argue that the existing legal framework is sufficient to manage the admissibility of LFR evidence. The primary argument in favour of the status quo is the flexibility of the discretion provided by section 78 of PACE. This provision was designed to handle precisely these kinds of situations, where new forms of evidence emerge from novel investigative techniques. It allows a judge to consider all the specific circumstances of a case, including the seriousness of the offence, the reliability of the technology, and the extent of any impropriety in how the evidence was obtained. This case-by-case approach avoids a rigid, blanket rule of inadmissibility that could hamper the investigation of serious crimes.
It can also be argued that the law has successfully adapted to previous technological advances, such as CCTV and DNA evidence, without the need for a specific statute governing their admissibility. The courts have developed principles through common law to handle the challenges posed by such evidence. Proponents might suggest that LFR is simply the next step in this evolution and that the judiciary can be trusted to develop appropriate safeguards through its application of section 78. The evidence from an LFR system is rarely the sole piece of evidence in a case; it is often an intelligence tool that points officers towards a suspect, who is then identified through other, more conventional means, such as by an eyewitness. In this context, it could be argued that concerns about the technology’s fallibility are overstated, as the LFR ‘match’ is merely the starting point of an investigation, not its conclusion.
However, these arguments under-appreciate the unique nature of LFR. Unlike conventional CCTV, which records passively, LFR is an active and analytical system that biometrically scans and identifies countless innocent people. It represents a more significant step-change in surveillance capability, moving from targeted to mass monitoring. The Court of Appeal in *Bridges* implicitly rejected the idea that the existing framework was adequate by ruling that the lack of a specific and clear legal basis rendered its use unlawful. Relying on an individual judge’s discretion under section 78 to fix such a fundamental illegality in the evidence-gathering process is not a sustainable or just solution.
Conclusion
In conclusion, the current legal framework governing the admissibility of evidence in England and Wales is not fit for purpose when it comes to live facial recognition. While the discretionary power under section 78 of PACE provides a safeguard for fair trials, it is insufficient to address the systemic challenges posed by LFR. The judgment in *Bridges* has clearly signalled that the deployment of this technology without a precise and foreseeable legal basis is unlawful. To then allow evidence derived from that unlawful process to be admitted in court on a case-by-case basis would be inconsistent and would undermine the rule of law.
The significant risks that LFR poses to the fundamental right to privacy, the potential for algorithmic bias to compromise fair trial rights, and the lack of democratic legitimacy all point towards the same conclusion. A dedicated statutory framework, passed by Parliament after full public and expert debate, is required. Such a statute should set out clear and strict rules for the authorisation and deployment of LFR, establish minimum standards for technical accuracy and fairness, and create transparent processes for how evidence is challenged in court. Until such a framework is in place, admitting LFR evidence would mean turning a blind eye to the profound legal and ethical problems at the heart of its use, and a cautious approach of inadmissibility should be adopted.
References
*Bridges, R (on the application of) v The Chief Constable of South Wales Police and others* [2020] EWCA Civ 1058
Data Protection Act 2018
Equality Act 2010
House of Commons Science and Technology Committee (2019) *The work of the Biometrics Commissioner and the Forensic Science Regulator. Oral evidence, HC 1910*. The Stationery Office.
Information Commissioner’s Office (2019) *Investigation into the use of live facial recognition technology by the Metropolitan Police Service at the Stratford site of the Westfield shopping centre*. ICO.
National Institute of Standards and Technology (NIST) (2019) *Face Recognition Vendor Test (FRVT) Part 3: Demographic Effects*. US Department of Commerce.
Police and Criminal Evidence Act 1984
