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Law enforcement agencies across the UK successfully lobbied to use a facial recognition system acknowledged as biased against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This admission followed a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept discrimination in ethnicity and sex. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was more likely to suggest false positives for images depicting women, individuals of Black ethnicity, 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 potential matches be increased to a level where the bias was greatly diminished.

However, this directive was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents indicate the stricter setting reduced the number of queries resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent independent review found the system could produce incorrect matches for Black women almost 100 times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The documents further note that police units argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its proposals to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

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: “There was scant consideration in equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be pursued without specialist personnel meticulously examining the results.”