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Police forces across the United Kingdom successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, youths, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the bias was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of queries resulting in potential matches from over half to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study discovered the system could produce incorrect matches for Black women nearly a hundred times more frequently than for white women at specific configurations.

The Home Office commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant discussion through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments the police has undertaken via the equality initiative are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We takes the conclusions of the study seriously 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 early next year and will be undergo further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”