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Police forces across the UK successfully lobbied to deploy a facial recognition system known to be discriminatory against females, young people, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The Home Office admitted last week that the system was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was intended to mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to produce false positives for images depicting women, Black people, 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 significantly reduced.

However, this decision was reversed the next month after forces complained that the adjusted system was producing fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate false positives for Black women almost 100 times more often than for Caucasian women at certain settings.

The Home Office commented on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

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

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion through equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has undertaken via the race action plan are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of this technology must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We takes the conclusions of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no further action would be pursued without specialist personnel meticulously examining the results.”