British Law Enforcement Agencies Campaign to Employ Biased Facial Recognition Systems

Police forces across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as discriminatory against females, youths, and members of minority ethnic backgrounds, following complaints that a less biased version produced fewer potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to carry out searches using historical face recognition. This procedure entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the system was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept biases in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

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

However, this directive was reversed the next month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of searches that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these results: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The papers add that forces complained that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week public review on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, commented: “There was very little discussion through race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the pledges to combat discrimination the police has undertaken via the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection already persist.

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

Official Statement

A Home Office spokesperson stated: “We takes the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without specialist personnel carefully reviewing the results.”