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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

British police use the police national database (PND) to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a suspect against a database of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate biases in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to suggest incorrect matches for photos of females, Black people, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the following month after forces complained that the modified technology was generating fewer “investigative leads”. Internal records show the higher threshold reduced the number of queries that yielded possible identifications from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the latest independent review discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the police records note: “This adjustment greatly lessens the impact of bias across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was very little consideration through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“These revelations show yet again that the anti-racism commitments the police has made through the race action plan are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without trained officers meticulously examining the output.”