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Police forces across the UK successfully lobbied to deploy a face scanning system known to be biased against women, youths, and individuals from ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

How the System Works

British police use 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 more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This acknowledgment came after a review 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 Home Office said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users accept biases in race and sex. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been recognized for more than a year. 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 late 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

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

However, this decision was overturned the following month after forces complained that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of searches resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the latest independent review found the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The documents further note that forces complained that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “We observed scant discussion in equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination the police has made through the race action plan are not being translated into broader operations. Our reports have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the study with utmost gravity and we have already taken action. A updated software 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.

“Our priority is protecting the public. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be pursued without trained officers meticulously examining the output.”