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Police forces across the UK effectively campaigned to use a facial recognition system acknowledged as discriminatory against females, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated fewer potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This procedure entails comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address 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 incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be raised to a point where the disparity was greatly diminished.

However, this decision was overturned the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. Internal records indicate the higher threshold cut the proportion of searches that yielded possible identifications from over half to a just 14%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest independent review discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The papers further note that police units complained that “a previously useful tool returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the police race action plan, commented: “We observed scant consideration through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has undertaken through the race action plan are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

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

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“Our priority is protecting the public. 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 carefully reviewing the output.”