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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against females, youths, and members of minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a repository of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This admission followed a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and women at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse 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 concluded the system was had a higher probability to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the following month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of searches resulting in possible identifications from over half to a just under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the latest independent review discovered the system could generate incorrect matches for Black women nearly a hundred times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “The testing found that in a specific scenarios the software is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

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 technology as the “most significant advance since DNA matching”.

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: “We observed very little discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made via the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

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

Official Statement

A Home Office spokesperson stated: “We treat the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support 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 specialist personnel meticulously examining the output.”