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Police forces across the UK successfully lobbied to use a face scanning system acknowledged as discriminatory against women, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated fewer potential suspects.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This procedure entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was overturned the following month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of searches that yielded possible identifications from 56% to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study found the system could generate incorrect matches for Black women nearly a hundred times more often than for white women at certain settings.

The ministry commented on these results: “Our evaluation found that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The papers add that forces argued that “a previously useful tool returned 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. The minister for police Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant discussion in race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has undertaken through the race action plan are not being translated into broader operations. Our reports have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A government representative stated: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel meticulously examining the output.”