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Police forces across the United Kingdom effectively campaigned to use a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This process involves matching a “probe image” of a suspect against a repository of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

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

Known Issue

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

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this decision was overturned the following month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of searches that yielded possible identifications from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study found the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “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 note: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on police efficiency”. The documents further note that forces argued that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has undertaken via the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers carefully reviewing the output.”