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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system known to be biased against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process entails matching a reference photograph of a suspect against a repository of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest incorrect matches for images depicting women, 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 potential matches be increased to a point where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting reduced the proportion of queries that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the latest NPL study discovered the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to expand the use of facial recognition technology. 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 advisory panel for the national policing equality strategy, commented: “We observed scant consideration in race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that new technologies are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to 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 treat the findings of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without specialist personnel meticulously examining the output.”