British Police Forces Campaign to Use Discriminatory Facial Recognition Systems

Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be discriminatory against females, young people, and members of ethnic minority groups, following complaints that a more accurate version generated fewer potential suspects.

The Technology in Practice

British police 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 repository 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 admission came after a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“This raises the question of whether facial recognition only becomes useful if users accept biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce false positives for photos of women, individuals of Black ethnicity, 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 level where the disparity was significantly reduced.

However, this directive was overturned the next month after forces complained that the adjusted system was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the number of searches that yielded possible identifications from 56% to a mere 14%.

Severe Disparities

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

The ministry commented on these findings: “The testing identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that police units complained that “a once effective tactic returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration through equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken via the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

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 no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no arrest or charge would be pursued without trained officers meticulously examining the results.”