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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces use the national police database to conduct retrospective facial recognition searches. This procedure involves matching a reference photograph of a suspect against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes effective if users accept biases in race and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn 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 concluded the system was had a higher probability to produce false positives for images depicting females, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the stricter setting reduced the number of queries resulting in potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the NPCC documents note: “The change greatly lessens the impact of bias across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a previously useful tool 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. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

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

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”