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Police forces across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This process involves comparing a reference photograph of a suspect against a repository of over 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office conceded last week that the system was flawed. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and women at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce false positives for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a point where the disparity was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of queries that yielded possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the recent independent review discovered the system could produce false positives for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the impact of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative stated: “We treat the findings of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

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