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Police forces across the United Kingdom 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 generated a reduced number of investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females 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 effective if users accept biases in race and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was had a higher probability to suggest 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 significantly reduced.

However, this decision was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of searches that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

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

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

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of bias across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that forces argued that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand 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

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, said: “We observed scant discussion in equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “The Home Office takes the findings of the report seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no further action would be pursued without trained officers meticulously examining the results.”