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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system known to be biased against females, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version generated fewer potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a repository of over 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at much greater frequency than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to produce false positives for photos of females, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a point where the bias was greatly diminished.

However, this decision was overturned the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of queries resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the authorities declined to specify what setting is now in operation, the recent independent review found the system could produce false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

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

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “There was very little consideration through equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

“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 process and no further action would be pursued without specialist personnel meticulously examining the results.”