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Police forces across the UK successfully lobbied to use a facial recognition system known to be discriminatory against women, youths, and members of ethnic minority groups, after complaining that a less biased version generated a reduced number of potential suspects.

The Technology in Practice

British police utilize the national police database to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a database of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended 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 suggest incorrect matches for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the disparity was significantly reduced.

However, this directive was overturned the following month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. NPCC documents show the stricter setting cut the proportion of searches resulting in possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the recent NPL study found the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a specific scenarios the algorithm is more likely to wrongly flag 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 NPCC documents state: “The change greatly lessens the impact of bias across legally safeguarded attributes of race, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that forces complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “We observed scant discussion through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“These revelations show once again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

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

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 procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”