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Law enforcement agencies across the United Kingdom successfully lobbied to use a facial recognition system known to be discriminatory against females, youths, and individuals from ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This process entails comparing a reference photograph of a suspect against a database of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This admission came after a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in race and sex. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a point where the disparity was significantly reduced.

However, this decision was reversed the following month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the number of queries that yielded potential matches from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest NPL study found the system could produce incorrect matches for Black women nearly a hundred times more frequently than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units argued that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “There was scant discussion in equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations show once again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into wider practice. Our reports have warned that innovative tools are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds 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 new algorithm has been independently tested 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 support police to put criminals and rapists behind bars. There is officer review in each stage of the process and no arrest or charge would be taken without specialist personnel meticulously examining the output.”