🔗 Share this article

Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against women, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer potential suspects.

How the System Works

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

Admitted Bias

The UK interior ministry admitted last week that the system was biased. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users accept discrimination in race and sex. Operational ease is a weak argument for disregarding basic freedoms.”

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 September 2024. The government-ordered laboratory study found the system was had a higher probability to suggest false positives for photos of females, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a point where the bias was significantly reduced.

However, this decision was reversed the next month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the number of searches resulting in possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the authorities refused to say what threshold 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 white women at specific configurations.

The Home Office stated on these results: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The papers add that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has described the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

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

“This disclosure demonstrate yet again that the anti-racism commitments the police has made via the race action plan are not being translated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We takes the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be taken without trained officers meticulously examining the output.”