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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against women, young people, and individuals from ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

How the System Works

British police utilize the national police database to carry out searches using historical face recognition. This procedure involves comparing a reference photograph of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The Home Office stated it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in ethnicity and sex. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest false positives for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the accuracy setting required for possible hits be increased to a point where the disparity was greatly diminished.

However, this decision was reversed the following month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold cut the number of queries that yielded potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the latest independent review found the system could generate false positives for women of Black heritage almost 100 times more often than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a specific scenarios the software is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase 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 police efficiency”. The documents add that forces complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed very little discussion through race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination the police has made through the race action plan are not being translated into broader operations. Our reports have warned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We takes the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, 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 gamechanging technology will support police to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without specialist personnel meticulously examining the results.”