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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system known to be biased against women, youths, and members of minority ethnic backgrounds, following complaints that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

UK forces use the national police database to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users accept biases in race and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce false positives for images depicting females, Black people, 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 level where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the number of queries that yielded possible identifications from over half to a mere 14%.

Profound Inequalities

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

The Home Office stated on these findings: “The testing identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration in race action plan meetings of the technology deployment despite clear relevance with the strategy's goals.

“These revelations show once again that the anti-racism commitments the police has undertaken through the race action plan are not being translated into wider practice. Our reports have warned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “We takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”