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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

British police use the national police database to carry out retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission followed a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the proportion of queries resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the recent NPL study discovered the system could generate false positives for Black women almost 100 times more often than for white women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the impact of discrimination across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. The minister for police Sarah Jones has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, said: “We observed scant discussion through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments policing has undertaken through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be taken without trained officers meticulously examining the results.”