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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system known to be discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This acknowledgment came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a level where the bias was significantly reduced.

However, this decision was reversed the next month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records show the stricter setting reduced the number of searches resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the police records state: “The change 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 further note that police units argued that “a previously useful tool returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

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

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken through the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“Our priority is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be pursued without trained officers carefully reviewing the output.”