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Law enforcement agencies across the UK effectively campaigned to use a face scanning system known to be discriminatory against females, young people, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This process entails comparing a “probe image” of a person of interest against a repository of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users accept discrimination in race and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body ordered 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 next month following complaints from police that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records indicate the stricter setting cut the proportion of queries resulting in 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 latest independent review discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry stated on these results: “The testing found that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “This adjustment greatly lessens the impact of bias across protected characteristics of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of facial recognition technology. Policing minister Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “We observed very little consideration in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations show once again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have warned that new technologies are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “We treat the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police 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 results.”