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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be biased against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police utilize the national police database to conduct retrospective facial recognition searches. This process involves matching a reference photograph of a person of interest against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office admitted last week that the system was biased. This acknowledgment followed 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 white men. The Home Office stated it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept biases in race and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was more likely to suggest false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be increased to a point where the bias was significantly reduced.

However, this directive was reversed the following month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents show the higher threshold reduced the number of searches resulting in possible identifications from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the latest NPL study found 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 stated on these findings: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of bias across protected characteristics of race, generation and gender but had a significant negative impact on operational effectiveness”. The papers add that police units complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones 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: “We observed very little discussion in equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has undertaken through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office treat the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“Our priority is protecting the public. This revolutionary tool will support police to put criminals and rapists behind bars. There is officer review in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”