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Police forces across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This process entails matching a reference photograph of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

“This raises the question of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were notified of the system's bias in late 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a point where the disparity was greatly diminished.

However, this directive was overturned the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of queries that yielded possible identifications from over half to a just 14%.

Profound Inequalities

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

The Home Office commented on these findings: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The documents add that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the police race action plan, said: “We observed very little consideration in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations show once again that the pledges to combat discrimination the police has undertaken through the equality initiative are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without specialist personnel meticulously examining the results.”