🔗 Share this article

Law enforcement agencies across the United Kingdom successfully lobbied to use a face scanning system known to be discriminatory against females, youths, and members of ethnic minority groups, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

UK forces use the police national database (PND) to conduct searches using historical face recognition. This procedure entails comparing a reference photograph of a suspect against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “took steps on the findings”.

“This raises the question of whether this technology only becomes useful if users accept discrimination in race and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

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

Police bosses were notified of the system's bias in late 2024. The government-ordered laboratory study found the system was more likely to suggest false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

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 greatly diminished.

However, this decision was overturned the following month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of queries that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent NPL study discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “We observed very little discussion in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination policing has made via the equality initiative are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the findings of the study seriously and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without trained officers carefully reviewing the output.”