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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against women, youths, and members of ethnic minority groups, after complaining that a more accurate version produced a reduced number of potential suspects.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This procedure involves matching a “probe image” of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

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

Known Issue

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was had a higher probability to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a level where the bias was greatly diminished.

However, this directive was reversed the next month following complaints from police that the adjusted system was producing fewer “investigative leads”. Internal records indicate the stricter setting reduced the proportion of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the latest independent review discovered the system could produce false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The ministry stated on these findings: “The testing identified that in a specific scenarios the software is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration 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 labeled the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “There was very little consideration in equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“Any use of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “The Home Office takes the findings of the report seriously and we have implemented changes. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without specialist personnel carefully reviewing the output.”