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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of potential suspects.

How the System Works

British police utilize the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in ethnicity and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was more likely to suggest false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

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

However, this decision was reversed the next month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

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

The Home Office commented on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the impact of discrimination across protected characteristics of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents further note that forces complained that “a once effective tactic now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made via the equality initiative are not being translated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must meet strict national standards, be subject to external review, 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 report with utmost gravity 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 subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be taken without trained officers carefully reviewing the output.”