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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as biased against women, young people, and members of ethnic minority groups, after complaining that a less biased version produced fewer investigative leads.

The Technology in Practice

British police use the national police database to carry out searches using historical face recognition. This process entails matching a “probe image” of a person of interest against a database of more than 19 million mugshots to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was flawed. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in race and sex. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was more likely to produce false positives for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a point where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the adjusted system was producing a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the proportion of searches resulting in possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is now in operation, the latest NPL study found the system could produce incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a limited set of circumstances the software is more likely to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units complained that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week 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”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was scant discussion through race action plan meetings of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the output.”