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Police forces across the UK effectively campaigned to deploy a face scanning system known to be discriminatory against females, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate biases in race and gender. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers show that this bias has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce 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 leadership body ordered that the confidence threshold required for potential matches be raised to a point where the disparity was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of searches that yielded possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the latest NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing identified that in a limited set of circumstances the algorithm is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The papers further note 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 consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed very little consideration in race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson stated: “We takes the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without trained officers carefully reviewing the results.”