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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This procedure involves matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate discrimination in ethnicity and gender. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a level where the bias was significantly reduced.

However, this decision was reversed the next month after forces complained that the modified technology was producing fewer “investigative leads”. Internal records indicate the higher threshold reduced the number of searches that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest independent review found the system could produce false positives for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The ministry 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 match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “There was scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has undertaken via the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We takes the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will support police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers meticulously examining the results.”