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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 minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of potential suspects.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This procedure entails comparing a reference photograph of a suspect against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This acknowledgment followed a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in race and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in September 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 under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a level where the disparity was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was producing fewer “investigative leads”. Internal records indicate the higher threshold cut the number of queries resulting in potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the recent NPL study discovered the system could generate false positives for Black women nearly a hundred times more often than for white women at specific configurations.

The ministry stated on these results: “The testing identified that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's confidence threshold, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “We observed scant consideration through race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken through the equality initiative are not being translated into wider practice. Our reports have warned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative said: “The Home Office takes the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be taken without trained officers meticulously examining the results.”