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Law enforcement agencies across the UK successfully lobbied to use a face scanning system acknowledged as 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 searches using historical face recognition. This procedure involves matching a “probe image” of a person of interest against a repository of more than 19 million mugshots to find possible hits.

Admitted Bias

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

“It prompts the question of whether this technology only becomes effective if users accept discrimination in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to suggest false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the number of searches resulting in potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest independent review discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The documents further note that forces argued that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “There was scant discussion in equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has made through the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the findings of the study with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”