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Law enforcement agencies across the United Kingdom successfully lobbied to use a face scanning system acknowledged as discriminatory against females, youths, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces utilize the national police database to carry out retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at much greater frequency than white men. The ministry stated it “took steps on the findings”.

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

Long-Standing Problem

Official papers reveal that this bias has been known about for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered laboratory study concluded the system was more likely to produce false positives for images depicting females, 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 confidence threshold required for potential matches be raised to a level where the disparity was greatly diminished.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the proportion of searches resulting in potential matches from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest independent review found the system could generate false positives for Black women almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office stated on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

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

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 consideration through race action plan meetings of the technology deployment 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 not being translated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, 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 prove it diminishes rather than compounds ethnic bias.”

Home Office Response

A government representative said: “The Home Office takes the conclusions of the study with utmost gravity 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 in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be taken without trained officers meticulously examining the results.”