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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against women, young people, and individuals from minority ethnic backgrounds, after complaining that a more accurate 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 process involves comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office conceded last week that the technology was flawed. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “had acted on the findings”.

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

Long-Standing Problem

Internal documents show that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability to suggest false positives for photos of females, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be increased to a point where the disparity was significantly reduced.

However, this decision was overturned the next month following complaints from police that the modified technology was generating fewer “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the recent independent review discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The Home Office stated on these results: “The testing identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The documents further note that police units complained that “a once effective tactic returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to widen 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, commented: “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 pledges to combat discrimination policing has undertaken through the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be pursued without trained officers meticulously examining the results.”