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Police forces across the UK effectively campaigned to deploy a face scanning system known to be biased against women, youths, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer potential suspects.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct searches using historical face recognition. This procedure involves comparing a reference photograph of a person of interest against a repository of over 19 million custody photos to identify potential matches.

Admitted Bias

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

“This raises the question of whether facial recognition only becomes useful if users accept discrimination in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was intended to address the problem.

Police bosses were informed of the system's bias in late 2024. The government-ordered NPL review found the system was more likely to produce false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records indicate the higher threshold reduced the proportion of queries that yielded potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest NPL study discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records note: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces argued that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened 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 technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed scant consideration through race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments policing has made via the equality initiative are not being translated into broader operations. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We takes the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”