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Police forces across the UK effectively campaigned to use a face scanning system known to be biased against women, young people, and individuals from ethnic minority groups, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This admission came after a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate biases in race and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

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

However, this decision was reversed the following month after forces complained that the modified technology was generating a lower number of “investigative leads”. NPCC documents show the higher threshold cut the number of queries that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the recent NPL study discovered the system could produce false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office stated on these findings: “The testing identified that in a specific scenarios the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of bias across protected characteristics 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 now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little discussion through race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has undertaken via the equality initiative are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative stated: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel meticulously examining the output.”