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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system known to be biased against women, youths, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a suspect against a database of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it incorrectly matched 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 accept biases in race and sex. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for photos of 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 accuracy setting required for possible hits be raised to a point where the disparity was greatly diminished.

However, this directive was overturned the next month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. NPCC documents show the stricter setting reduced the proportion of searches resulting in potential matches from 56% to a just 14%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the recent NPL study found the system could produce incorrect matches for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation found that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of bias across protected characteristics of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The documents add that police units complained that “a previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little discussion in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments the police has made via the equality initiative are not being translated into wider practice. Our reports have warned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be pursued without trained officers meticulously examining the results.”