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Police forces across the UK effectively campaigned to deploy a face scanning system known to be biased against females, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This procedure involves comparing a reference photograph of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

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

“It prompts the issue of whether facial recognition only becomes useful if users tolerate biases in race and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was reversed the next month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents show the stricter setting reduced the proportion of queries that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the latest NPL study discovered the system could produce false positives for Black women nearly a hundred times more often than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of bias across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a once effective tactic now delivered 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 facial recognition technology. The minister for police Sarah Jones has labeled 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 police race action plan, said: “We observed very little consideration through equality strategy sessions of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments the police has made via 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 racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office treat the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. 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 further action would be taken without specialist personnel meticulously examining the output.”