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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 members of ethnic minority groups, after complaining that a more accurate version generated fewer investigative leads.

How the System Works

UK forces use the national police database to carry out retrospective facial recognition searches. This procedure involves comparing a “probe image” of a person of interest against a database of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was biased. This acknowledgment followed a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were notified of the system's bias in late 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the following month after forces complained that the modified technology was producing fewer “investigative leads”. NPCC documents indicate the higher threshold cut the proportion of queries resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is now in operation, the latest independent review discovered the system could generate incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The ministry commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of bias across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little consideration through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to strict national standards, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We takes the findings of the report seriously and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”