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

The Technology in Practice

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This process involves comparing a “probe image” of a suspect against a database of over 19 million custody photos to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was flawed. This admission came after a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal 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.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability to suggest false positives for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a point where the disparity was significantly reduced.

However, this decision was reversed the following month following complaints from police that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting reduced the number of searches that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the latest independent review discovered 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 findings: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the effect of discrimination across protected characteristics of race, age and gender but had a significant negative impact on police efficiency”. The papers add that forces complained that “a once effective tactic now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, said: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination policing has undertaken via the race action plan are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

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

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be pursued without trained officers carefully reviewing the results.”