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Police forces across the United Kingdom successfully lobbied to use a face scanning system known to be biased against females, young people, and members of minority ethnic backgrounds, following complaints that a less biased version generated a reduced number of potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves comparing a reference photograph of a suspect against a database of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The Home Office stated it “took steps on the findings”.

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

Known Issue

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was overturned the following month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded possible identifications from 56% to a mere under 15%.

Severe Disparities

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

The ministry stated on these results: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on operational effectiveness”. The papers further note that police units complained that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled 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, commented: “There was very little consideration through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken through the race action plan are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the findings of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“Our priority is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be taken without trained officers meticulously examining the results.”