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Police forces across the UK effectively campaigned to use a face scanning system known to be biased against females, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of potential suspects.

How the System Works

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes useful if users tolerate discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered NPL review concluded the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be raised to a point where the bias was significantly reduced.

However, this decision was reversed the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting cut the number of searches resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that forces argued that “a once effective tactic returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, commented: “There was very little discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A government representative stated: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”