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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

British police use the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in race and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been recognized for more than a year. 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 late 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest incorrect matches for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be raised to a point where the disparity was greatly diminished.

However, this decision was reversed the following month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records show the stricter setting reduced the number of searches resulting in potential matches from 56% to a mere under 15%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the recent NPL study discovered the system could generate incorrect matches for Black women almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing found 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

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to widen the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool 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, commented: “There was very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments policing has made via the race action plan are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “We takes the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without trained officers meticulously examining the output.”