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Police forces across the UK effectively campaigned to use a facial recognition system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version generated fewer investigative leads.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment came after a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

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

However, this directive was reversed the following month after forces complained that the modified technology was generating a lower number of “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent independent review discovered the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing identified that in a specific scenarios the algorithm 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 NPCC documents state: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “We observed scant discussion through race action plan meetings of the technology deployment despite obvious cross-over 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 broader operations. Our reports have cautioned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”