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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated fewer potential suspects.

The Technology in Practice

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

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This admission 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 said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be raised to a level where the bias was greatly diminished.

However, this decision was reversed the following month following complaints from police that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the higher threshold cut the number of searches that yielded potential matches from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest independent review found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the effect of bias across legally safeguarded attributes of race, age and sex but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “There was scant consideration through race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations show once again that the anti-racism commitments policing has made through the equality initiative are not being translated into broader operations. Independent assessments have cautioned that innovative tools 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 subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Official Statement

A government representative said: “The Home Office treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers carefully reviewing the results.”