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Police forces across the United Kingdom successfully lobbied to use a face scanning system acknowledged as biased against females, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This process entails comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate biases in race and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest false positives for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be increased to a point where the bias was greatly diminished.

However, this decision was overturned the following month following complaints from police that the adjusted system was producing fewer “investigative leads”. Internal records show the stricter setting cut the proportion of queries resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest independent review found the system could produce false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a limited set of circumstances the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents further note that police units argued that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed scant discussion through race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “The Home Office takes the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”