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Police forces across the UK successfully lobbied to deploy a facial recognition system known to be biased against females, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced a reduced number of investigative leads.

How the System Works

UK forces use the police national database (PND) to conduct searches using historical face recognition. This process entails comparing a reference photograph of a person of interest against a repository of over 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and women at significantly higher rates than white men. The ministry said it “took steps on the findings”.

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

Known Issue

Official papers reveal that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a point where the disparity was greatly diminished.

However, this directive was reversed the following month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the proportion of queries resulting in possible identifications from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest independent review discovered the system could generate false positives for Black women nearly a hundred times more often than for white women at certain settings.

The ministry commented on these results: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's accuracy setting, the police records note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents further note that police units argued that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of biometric scanning systems. The minister for police Sarah Jones has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “There was very little discussion through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“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 output.”