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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against women, young people, and members of ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

The Technology in Practice

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

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission 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 Caucasian males. The ministry said it “had acted on the findings”.

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

Long-Standing Problem

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

Police bosses were notified of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to suggest false positives for images depicting women, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body ordered that the accuracy setting required for possible hits be increased to a level where the disparity was greatly diminished.

However, this directive was overturned the next month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents show the higher threshold reduced the number of queries resulting in possible identifications from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest independent review found the system could produce false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation found that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The documents add that police units argued that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed very little consideration through 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 policing has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist police 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.”