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Police forces across the United Kingdom successfully lobbied to use a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, after complaining that a more accurate version produced fewer potential suspects.

The Technology in Practice

UK forces utilize 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 repository of over 19 million mugshots to find potential matches.

Admitted Bias

The Home Office conceded last week that the system was biased. This admission followed a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users accept discrimination in race and sex. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce false positives for images depicting 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 potential matches be increased to a point where the bias was greatly diminished.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. Internal records show the higher threshold cut the number of queries that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent independent review found the system could generate false positives for women of Black heritage almost 100 times more often than for white women at certain settings.

The Home Office stated on these findings: “Our evaluation found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the impact of bias across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The papers add that police units argued that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, commented: “There was very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments policing has undertaken through the equality initiative are not being translated into wider practice. Our reports have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We treat the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be pursued without specialist personnel meticulously examining the output.”