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Police forces across the UK successfully lobbied to use a face scanning system acknowledged as discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the national police database to carry out retrospective facial recognition searches. This process involves comparing a “probe image” of a suspect against a repository of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission followed a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The ministry said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept biases in ethnicity and sex. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to suggest false positives for images depicting women, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body ordered that the accuracy setting required for possible hits be increased to a point where the disparity was greatly diminished.

However, this decision was reversed the following month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting reduced the number of queries resulting in potential matches from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study found the system could generate false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on police efficiency”. The documents add that police units argued that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “We observed scant consideration in equality strategy sessions of the technology deployment despite clear relevance 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 not being translated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “We takes the conclusions of the report with utmost gravity and we have implemented changes. 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.

“Our priority is ensuring public safety. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”