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Law enforcement agencies across the UK successfully lobbied to use a face scanning system acknowledged as discriminatory against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves comparing a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. 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 Caucasian males. The ministry said it “took steps on the findings”.

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

Long-Standing Problem

Internal documents show that this bias 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 September 2024. The government-ordered NPL review found the system was more likely to suggest false positives for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a point where the bias was significantly reduced.

However, this decision was overturned the following month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of searches that yielded possible identifications from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces argued that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “We observed very little consideration in equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has undertaken through the equality initiative 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 poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative said: “We takes the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”