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Police forces across the UK effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a less biased version produced fewer investigative leads.

How the System Works

UK forces use the national police database to conduct retrospective facial recognition searches. This procedure entails comparing a reference photograph of a person of interest against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The Home Office stated it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in race and sex. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

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

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest false positives for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a point where the disparity was greatly diminished.

However, this directive was overturned the following month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents show the higher threshold cut the number of queries that yielded potential matches from 56% to a just under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the recent independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing found that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “The change significantly reduces the impact of bias across protected characteristics of race, generation and gender but had a substantially detrimental effect on police efficiency”. The papers add that police units argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was scant discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken via the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “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 evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”