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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as discriminatory against women, young people, and members of ethnic minority groups, after complaining that a less biased version generated fewer potential suspects.

The Technology in Practice

UK forces utilize the national police database to carry out searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office conceded last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at much greater frequency than white men. The ministry said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study 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 Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a point where the disparity was greatly diminished.

However, this decision was overturned the following month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents show the stricter setting reduced the number of searches resulting in potential matches from over half to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the recent independent review found the system could generate false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include 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 NPCC documents state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that police units argued that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “There was very little consideration in race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken through the race action plan are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it reduces rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We takes the findings of the study seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This gamechanging technology will assist 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 trained officers carefully reviewing the results.”