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Police forces across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against females, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

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

Admitted Bias

The Home Office admitted last week that the system was flawed. This admission followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

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

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to address the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a point where the bias was greatly diminished.

However, this decision was overturned the following month after forces complained that the modified technology was generating a lower number of “investigative leads”. NPCC documents indicate the stricter setting reduced the number of searches that yielded possible identifications from 56% to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what threshold 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 white women at specific configurations.

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

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the effect of bias across protected characteristics of race, age and sex but had a substantially detrimental effect on police efficiency”. The papers add that police units complained that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “We observed scant consideration through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has made via the equality initiative are not being translated into broader operations. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months 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 officer review in each stage of the procedure and no arrest or charge would be taken without trained officers meticulously examining the results.”