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Law enforcement agencies across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against females, young people, and individuals from minority ethnic backgrounds, following complaints that a less biased version generated fewer potential suspects.

The Technology in Practice

UK forces utilize the national police database to carry out retrospective facial recognition searches. This process involves matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission followed a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“This raises the question of whether this technology only becomes useful if users accept biases in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

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 designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest false positives for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was overturned the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of queries resulting in possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest independent review found the system could produce false positives for Black women almost 100 times more frequently than for white women at certain settings.

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

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the police records note: “The change significantly reduces the effect of bias across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

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 consideration through race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “We treat the findings of the report seriously and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be tested early next year and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be pursued without trained officers meticulously examining the output.”