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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This procedure entails matching a reference photograph of a suspect against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the system was biased. This admission came after a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept discrimination in race and gender. Convenience is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents reveal that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was intended to address the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

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 level where the disparity was significantly reduced.

However, this directive was reversed the next month following complaints from police that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of queries that yielded possible identifications from 56% to a just under 15%.

Severe Disparities

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

The Home Office stated on these findings: “The testing found that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, commented: “There was very little discussion in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken through the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

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

Home Office Response

A Home Office spokesperson said: “We takes the findings of the study seriously and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the process and no arrest or charge would be taken without specialist personnel meticulously examining the output.”