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Police forces across the UK effectively campaigned to use a facial recognition system known to be discriminatory against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer investigative leads.

The Technology in Practice

British police utilize the national police database to conduct retrospective facial recognition searches. This process involves comparing a “probe image” of a suspect against a database of over 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was flawed. This admission followed a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

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

Senior officers were notified 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 images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for possible hits be increased to a level where the bias was greatly diminished.

However, this decision was reversed the next month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the stricter setting cut the number of searches that yielded potential matches from 56% to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the recent NPL study found the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry stated 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

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to widen the use of facial recognition technology. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “We observed very little discussion in race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has made through the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative stated: “We takes the conclusions of the study seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be pursued without trained officers meticulously examining the output.”