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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated fewer potential suspects.

How the System Works

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process entails comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This acknowledgment followed a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate discrimination in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a point where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. Internal records indicate the stricter setting cut the proportion of searches resulting in possible identifications from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent independent review found the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The documents add that police units argued that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month 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 “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant consideration through race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the anti-racism commitments the police has undertaken via the race action plan are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A government representative stated: “We treat the conclusions of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

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