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Police forces across the UK successfully lobbied to deploy a face scanning system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a less biased version generated fewer potential suspects.

The Technology in Practice

British police use the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a database of over 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The government-ordered laboratory study concluded the system was more likely to produce false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was reversed the following month after forces complained that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded possible identifications from 56% to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest independent review found the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

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

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “most significant advance 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 equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has made via the equality initiative are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the findings of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“Our priority 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 process and no arrest or charge would be pursued without trained officers carefully reviewing the results.”