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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against women, youths, and members of ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

British police use the police national database (PND) to carry out searches using historical face recognition. This procedure entails comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to find potential matches.

Admitted Bias

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

“It prompts the question of whether this technology only becomes useful if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Official papers show that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered NPL review found the system was had a higher probability to produce incorrect matches for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the disparity was significantly reduced.

However, this decision was overturned the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents show the stricter setting cut the proportion of queries resulting in potential matches from 56% to a just under 15%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the latest independent review discovered the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change significantly reduces the effect of discrimination across protected characteristics of race, generation and gender but had a significant negative impact on police efficiency”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week public review on its proposals to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “We observed scant discussion in race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments policing has made through the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the conclusions of the report with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be pursued without trained officers meticulously examining the output.”