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Police forces across the United Kingdom effectively campaigned to use a face scanning system known to be biased against females, youths, and members of minority ethnic backgrounds, following complaints that a less biased version produced fewer potential suspects.

The Technology in Practice

British police use the national police database to carry out retrospective facial recognition searches. This process entails matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the technology was flawed. This admission followed a study by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept discrimination in ethnicity and gender. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce 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 confidence threshold required for possible hits be increased to a point where the bias was significantly reduced.

However, this directive was reversed the following month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the number of searches resulting in potential matches from 56% to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest NPL study found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these results: “The testing found that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that police units complained that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to widen the use of facial recognition technology. The minister for police 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, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant discussion through race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office takes the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no arrest or charge would be taken without trained officers meticulously examining the output.”