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Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against females, youths, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer potential suspects.

How the System Works

UK forces utilize the national police database to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a suspect against a database of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users tolerate discrimination in race and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was designed to mitigate the problem.

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

However, this directive was overturned the following month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the proportion of searches resulting in possible identifications from 56% to a just 14%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the recent independent review discovered the system could generate false positives for Black women almost 100 times more often than for white women at certain settings.

The Home Office stated on these results: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment greatly lessens the effect of bias across protected characteristics of ethnicity, age and gender but had a significant negative impact on police efficiency”. The papers further note that forces argued that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was very little consideration in equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations show once again that the anti-racism commitments the police has made through the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of this technology must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the results.”