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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as biased against females, youths, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails matching a “probe image” of a person of interest against a database of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“This raises the question of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered 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 reaction, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a point where the bias was greatly diminished.

However, this decision was reversed the following month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of searches resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the latest NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office stated on these results: “Our evaluation found that in a limited set of circumstances the algorithm 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 impact of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the technology 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 in race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be taken without trained officers carefully reviewing the output.”