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Law enforcement agencies across the United Kingdom successfully lobbied to use a facial recognition system known to be discriminatory against women, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version produced fewer potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This procedure involves comparing a “probe image” of a person of interest against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users accept discrimination in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this bias has been known about for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was intended to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the following month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. NPCC documents show the stricter setting cut the proportion of queries resulting in possible identifications from 56% to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the recent independent review discovered the system could produce incorrect matches for Black women nearly a hundred times more often than for white women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination the police has undertaken through the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without trained officers carefully reviewing the results.”