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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as discriminatory against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of potential suspects.

How the System Works

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

Admitted Bias

The Home Office conceded last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and sex. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

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

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to suggest false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the higher threshold reduced the proportion of queries resulting in possible identifications from 56% to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The ministry commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week public review on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination policing has made via the equality initiative are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the conclusions 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 tested in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no further action would be pursued without trained officers carefully reviewing the output.”