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Police forces across the UK successfully lobbied to deploy a facial recognition system known to be biased against females, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

British police use the national police database to carry out searches using historical face recognition. This procedure entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

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

Long-Standing Problem

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

Senior officers 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 under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a point where the disparity was greatly diminished.

However, this directive was reversed the following month following complaints from police that the adjusted system was producing fewer “investigative leads”. NPCC documents show the stricter setting reduced the number of searches resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the recent independent review found the system could generate false positives for Black women nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the impact of bias across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The documents further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its proposals to widen 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 national policing equality strategy, said: “There was very little consideration in equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken via the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “We treat the conclusions of the study seriously and we have already taken action. 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 evaluation.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be pursued without trained officers meticulously examining the results.”