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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This admission followed a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and females 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 discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be increased to a point where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting reduced the number of searches resulting in possible identifications from over half to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent NPL study discovered 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 stated on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued 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 expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has made through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative said: “We takes the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”