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Police forces across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against women, young people, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

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

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This admission followed a review by the National Physical Laboratory (NPL) found 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”.

“This raises the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The government-ordered NPL review concluded the system was more likely to suggest incorrect matches for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the bias was significantly reduced.

However, this directive was reversed the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents indicate the stricter setting reduced the number of queries resulting in potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest independent review found the system could produce false positives for Black women almost 100 times more often than for Caucasian women at certain settings.

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

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the impact of discrimination across protected characteristics of race, age and sex but had a substantially detrimental effect on police efficiency”. The papers add that police units argued that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “We observed scant discussion in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has undertaken through the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

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

Official Statement

A government representative stated: “We treat the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, 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 protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”