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Police forces across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a less biased version generated fewer investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate biases in race and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest incorrect matches for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for possible hits be increased to a point where the disparity was greatly diminished.

However, this decision was reversed the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold cut the number of searches that yielded potential matches from 56% to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the recent NPL study discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

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 substantially detrimental effect on operational effectiveness”. The documents further note that police units complained that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination the police has made via the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat 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 tested in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”