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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, 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 carry out retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office stated it “had acted on the findings”.

“This raises the question of whether this technology only becomes effective if users accept discrimination in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in late 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 confidence threshold required for possible hits be raised to a point where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the modified technology was generating fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest independent review discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these results: “The testing found that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The papers further note that police units argued that “a previously useful tool returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “We observed scant consideration in equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has undertaken through the equality initiative are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

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

Home Office Response

A Home Office spokesperson said: “The Home Office takes the findings of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be taken without trained officers meticulously examining the results.”