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Police forces across the UK successfully lobbied to use a face scanning system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the national police database to carry out searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a database of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

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

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in race and sex. Convenience is a weak argument for overriding basic freedoms.”

Known Issue

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a level where the bias was greatly diminished.

However, this directive was reversed the following month following complaints from police that the adjusted system was producing fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of searches that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the latest NPL study found the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at specific configurations.

The Home Office stated on these results: “The testing identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the effect of bias across protected characteristics of race, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion in race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken via the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative stated: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“Our priority is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel meticulously examining the results.”