🔗 Share this article

Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against females, youths, and members of ethnic minority groups, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office conceded last week that the system was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The Home Office said it “took steps on the findings”.

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

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of females, 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 raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the effect of bias across legally safeguarded attributes of race, age and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units argued that “a once effective tactic returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed scant consideration through race action plan meetings of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments the police has made through 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 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 exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the report seriously 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 early next year and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”