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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be biased against women, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

UK forces use the national police database to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify potential matches.

Admitted Bias

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

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show 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 mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study found the system was more likely to produce 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) mandated that the confidence threshold required for possible hits be increased to a point where the disparity was significantly reduced.

However, this directive was overturned the next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of searches resulting in possible identifications from over half to a just under 15%.

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 women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “This adjustment greatly lessens the impact of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “There was very little discussion in race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated 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 ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be taken without specialist personnel meticulously examining the results.”