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Law enforcement agencies across the United Kingdom successfully lobbied to use a facial recognition system acknowledged as discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced fewer investigative leads.

The Technology in Practice

UK forces use the national police database to carry out searches using historical face recognition. This procedure involves matching a reference photograph of a suspect against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage 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 gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

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

Senior officers were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for images depicting women, Black people, and those aged 40 and under.

A Reversed Decision

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

However, this directive was overturned the following month after forces complained that the adjusted system was producing fewer “investigative leads”. NPCC documents show the stricter setting reduced the proportion of searches resulting in possible identifications from 56% 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 generate incorrect matches for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

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

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the effect of bias across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that police units complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed very little discussion in race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the conclusions of the study seriously and we have already taken action. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be taken without specialist personnel meticulously examining the output.”