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Police forces across the United Kingdom effectively campaigned to use a face scanning system acknowledged as discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a “probe image” of a suspect against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate discrimination in race and gender. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

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

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this decision was overturned the following month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold cut the proportion of searches resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest NPL study discovered the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these results: “Our evaluation found that in a specific scenarios the algorithm is more likely to incorrectly include 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 NPCC documents state: “The change greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The papers further note that forces complained that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was very little discussion through equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments policing has made through the race action plan are not being translated into wider practice. Our reports have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“Our priority is protecting the public. This gamechanging technology will support officers 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 carefully reviewing the output.”