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Police facial recognition trials resemble a ‘Wild West’ with inadequate safeguards and oversight

Real-world trials of live facial recognition by police lack rigorous oversight and could lead to the removal of basic freedoms, says new research.

2 December 2025•4 min read
A CCTV camera mounted on a concrete wall.

Real-world trials of live facial recognition (LFR) by UK and European police lack rigorous oversight and could lead to the ’incremental and insidious removal’ of the conditions that underpin our basic freedoms, according to a new study.

Police testing of LFR systems in real-world settings is described as a ‘Wild West’ in urgent need of reform to put essential safeguards in place, according to research led by the University of Birmingham and Guanghua Law School.

Published in the journal Data & Policy, the study finds that law enforcement trials of facial recognition technology in the UK and Europe have failed to demonstrate clear benefits and are often undertaken without adequate compliance with legal and ethical obligations. Oversight and accountability from those deploying the tech is inadequate, highlighting the need for robust frameworks for real-world AI testing.

The research examines trials conducted by law enforcement agencies across London, Wales, Berlin and Nice between 2016 and 2020.

There is huge capacity for misuse and overreach in ways that interfere with rights to privacy, freedom of expression, freedom of assembly, and to go about one’s lawful activity in public without unjustified interference by the state.

Professor Karen Yeung, University of Birmingham

Karen Yeung, an interdisciplinary professorial fellow in law, ethics and informatics at Birmingham Law School at the University of Birmingham and co-author of the study, said: “It is vital to properly consider the highly powerful, intrusive and scalable properties of LFR. There is huge capacity for misuse and overreach in ways that interfere with rights to privacy, freedom of expression, freedom of assembly, and to go about one’s lawful activity in public without unjustified interference by the state.”

UK police forces have been increasingly keen to adopt facial recognition technologies, with reported use by police forces in London, South Wales, Essex, Manchester, West Yorkshire, Bedfordshire, Surrey, Sussex and Thames Valley, Hampshire and Cheshire. This has been actively supported by the Home Office, which announced in August this year a significant expansion in the rollout of LFR across the country.

Trials that come under scrutiny in the study include the 10 ’operational’ trials conducted by the London Metropolitan Police Service (MPS) between 2016 and 2019 and 69 conducted by South Wales Police between 2017 and 2020.

In-the-wild testing is an important opportunity to collect information about how LFR performs in real-world deployment environments. However, our comparative study found that previous trials have failed to take into account the socio-technical impacts.

Professor Karen Yeung, University of Birmingham

Case study – London Metropolitan Police Service

Between 2016 and 2019, the London Metropolitan Police Service (MPS) conducted ten “operational” trials of facial recognition technology (FRT). Unlike controlled volunteer-based tests, these trials targeted individuals wanted by the police, raising questions from the study’s authors about their classification as mere ‘trials’.

Key Findings

  • Nature of Trials: Yeung and Li argue that labelling these deployments as ‘trials’ is misleading, as the operations had real legal and social consequences for those arrested, resembling active policing rather than experimental testing.
  • Lack of attention to adverse impacts: The trials focused narrowly on seeking to identify and apprehend ‘wanted’ individuals, without attempting to assess adverse impacts.
  • Accurate matching does not equate to ‘effective’ outcomes: accurate matching of a person’s face to a digital watchlist does not equate with successful and lawful apprehension. It requires serious coordination across technical, organisational, and properly trained police officers on the ground, which the Met had not fully addressed.
  • Facial recognition image ‘watchlists’ were compiled on the basis of broad, amorphous categories of persons in addition to those wanted on outstanding arrest warrants, which appeared unlikely to satisfy the legal tests of necessity and proportion to lawfully justify their inclusion.
  • Police interference without lawful grounds
    • An LFR match alert alone does not constitute ‘reasonable suspicion’ that a person has been involved in the commission of a crime, a legal precondition for police authority to stop and detain individuals in the UK.
    • Individuals are not legally obliged to answer police questions unless reasonable suspicion exists.
  • Operational Practice: Despite these requirements, evaluations revealed a ‘presumption to intervene’ among officers, who routinely engaged individuals flagged by the algorithm.

Yeung added: “In-the-wild testing is an important opportunity to collect information about how LFR performs in real-world deployment environments. However, our comparative study found that previous trials have failed to take into account the socio-technical impacts of the systems in use, or to generate clear evidence of the operational benefits.”

Given the scope for interference with people’s rights, the study calls for clear guidance and governance frameworks to ensure trials meet rigorous legal, ethical, and scientific standards.

The researchers added that without a rigorous and full accounting of the technology’s effectiveness in producing its desired benefits - which is currently not taking place in either the UK or Europe - it ‘must pass an exceptionally high threshold’ to justify police use.

Notes for editors

For media inquiries please contact Ellie Hail, Communications Officer, University of Birmingham on +44 (0)7966 311 409. Out-of-hours, please call +44 (0) 121 414 2772.

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Featured staff

  • Professor Karen Yeung

    Interdisciplinary Professorial Fellow in Law, Ethics and Informatics

    Academic profile of Professor Karen Yeung, Interdisciplinary Professorial Fellow in Law, Ethics and Informatics at Birmingham Law School and the School of Computer Science, University of Birmingham

    Phone: +44 (0) 121 414 6298
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