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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as discriminatory against females, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct searches using historical face recognition. This process involves matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to suggest false positives for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a point where the disparity was significantly reduced.

However, this decision was overturned the following 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 queries that yielded possible identifications from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest independent review found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The ministry stated on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the effect of bias across protected characteristics of race, generation and gender 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 questionable value”.

Wider Implementation Proposals

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

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the police race action plan, said: “There was very little consideration through equality strategy sessions of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative said: “We takes the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the output.”