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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be discriminatory against women, youths, and members of ethnic minority groups, after complaining that a more accurate version produced 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 comparing a reference photograph of a suspect against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office admitted last week that the system was biased. This admission followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and gender. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

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

Police bosses were notified of the system's bias in late 2024. The government-ordered NPL review found the system was more likely to produce false positives for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a level where the disparity was greatly diminished.

However, this decision was reversed the following month following complaints from police that the modified technology was generating a lower number of “investigative leads”. Internal records show the higher threshold reduced the number of searches resulting in potential matches from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say 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 Caucasian women at specific configurations.

The ministry stated on these findings: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency 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 accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, age and sex but had a significant negative impact on operational effectiveness”. The papers add that police units argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

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

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination the police has made via the race action plan are not being translated into wider practice. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

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