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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system known to be biased against women, young people, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This procedure entails matching a “probe image” of a suspect against a database of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

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

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

Long-Standing Problem

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a level where the disparity was greatly diminished.

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”. NPCC documents show the higher threshold cut the number of queries resulting in possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest independent review discovered the system could produce incorrect matches for Black women nearly a hundred times more often than for white women at certain settings.

The ministry stated on these results: “The testing found that in a limited set of circumstances the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect 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, age and sex but had a significant negative impact on operational effectiveness”. The papers add that police units argued that “a once effective tactic now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, commented: “We observed very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments policing has undertaken through the equality initiative are not being translated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without trained officers carefully reviewing the results.”