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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

British police use the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves comparing a reference photograph of a suspect against a database of more than 19 million mugshots to find potential matches.

Admitted Bias

The Home Office admitted last week that the technology was biased. This admission followed a study by the government's National Physical Laboratory found it misidentified Black and Asian people and women at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“This raises the question of whether facial recognition only becomes effective if users accept discrimination in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a point where the disparity was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents show the stricter setting cut the proportion of searches resulting in potential matches from 56% to a just 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 Black women nearly a hundred times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The papers further note that forces complained that “a once effective tactic returned results of questionable value”.

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 Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed very little discussion in race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination the police has made through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must meet strict national standards, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat the conclusions 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 trialled in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no further action would be pursued without specialist personnel carefully reviewing the results.”