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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system known to be discriminatory against females, youths, and individuals from ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a database of over 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office conceded last week that the system was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at significantly higher rates than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in race and gender. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

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

However, this directive was reversed the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. Internal records show the higher threshold reduced the number of searches that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of discrimination across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The papers add that police units argued 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 plans to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “There was very little consideration in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has made through the equality initiative are not being translated into wider practice. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, 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 revolutionary tool will assist officers to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be pursued without trained officers meticulously examining the output.”