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Police forces across the UK successfully lobbied to use a facial recognition system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated fewer potential suspects.

How the System Works

British police utilize the police national database (PND) 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.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This acknowledgment came after a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was reversed the following month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting reduced the number of queries resulting in potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent independent review discovered the system could produce false positives for Black women nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records note: “The change significantly reduces the impact of bias across protected characteristics of race, age and sex but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed scant discussion through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination policing has undertaken via the race action plan are failing to be integrated into broader operations. Our reports have warned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “The Home Office treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without specialist personnel meticulously examining the output.”