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

How the System Works

UK forces use the national police database to carry out retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and women at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users accept biases in race and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability 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 Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a point where the disparity was significantly reduced.

However, this decision was reversed the next month after forces complained that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the higher threshold reduced the number of queries that yielded potential matches from over half to a just 14%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the latest independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

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

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the effect of bias across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a previously useful tool returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week public review on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant discussion through race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken via the equality initiative are failing to be integrated into broader operations. Our reports have warned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“Our priority is ensuring public safety. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”