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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be biased against females, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a database of over 19 million custody photos to find possible hits.

Admitted Bias

The Home Office admitted last week that the system was biased. This admission came after 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 Home Office said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate biases in ethnicity and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the bias was greatly diminished.

However, this directive was overturned the following month after forces complained that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of searches resulting in possible identifications from 56% to a mere under 15%.

Profound Inequalities

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 nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of facial recognition technology. Policing minister Sarah Jones has described the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, said: “There was scant discussion in race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations show yet again that the anti-racism commitments the police has made via the race action plan are not being translated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “The Home Office treat the findings of the study with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in every step of the process and no arrest or charge would be pursued without trained officers meticulously examining the output.”