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Police forces across the UK effectively campaigned to use a face scanning system known to be discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer potential suspects.

The Technology in Practice

UK forces utilize the national police database to carry out retrospective facial recognition searches. This procedure entails comparing a “probe image” of a person of interest against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the question of whether this technology only becomes effective if users accept biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers 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 mitigate the problem.

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

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be raised to a level where the disparity was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of searches that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent independent review discovered the system could generate incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The ministry commented on these findings: “The testing found that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the effect of discrimination across protected characteristics of race, generation and gender but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

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

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “There was scant discussion in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has made through the race action plan are not being translated into wider practice. Our reports have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat 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 trialled in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without trained officers meticulously examining the results.”