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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against women, youths, and members of minority ethnic backgrounds, following complaints that a less biased version produced fewer potential suspects.

The Technology in Practice

British police use the police national database (PND) to carry out searches using historical face recognition. This procedure involves matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office conceded last week that the technology was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was more likely to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was overturned the following month following complaints from police that the modified technology was generating a lower number of “investigative leads”. NPCC documents show the stricter setting cut the proportion of queries that yielded possible identifications from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest independent review found the system could generate incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The ministry stated on these findings: “The testing identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that police units complained that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant discussion in race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments the police has undertaken via the race action plan are not being translated into wider practice. Independent assessments have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative stated: “We takes the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without specialist personnel meticulously examining the output.”