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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against women, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced fewer potential suspects.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a database of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry admitted 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 much greater frequency than white men. The ministry said it “had acted on the findings”.

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

Long-Standing Problem

Internal documents show that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to suggest false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a level where the bias was greatly diminished.

However, this directive was reversed the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of queries that yielded possible identifications from over half to a just 14%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the recent independent review discovered the system could generate false positives for Black women almost 100 times more frequently than for white women at certain settings.

The ministry stated on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on operational effectiveness”. The papers further note that forces complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its proposals 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”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed very little consideration in equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into wider practice. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “We treat the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested 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 protecting the public. This revolutionary tool will support police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers meticulously examining the output.”