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Law enforcement agencies across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version generated fewer investigative leads.

The Technology in Practice

UK forces use the national police database to carry out searches using historical face recognition. This procedure involves comparing a reference photograph of a suspect against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission followed a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

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

Known Issue

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

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce incorrect matches for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was generating a lower number of “investigative leads”. Internal records indicate the stricter setting reduced the number of searches that yielded potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the recent NPL study discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office stated on these findings: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the effect of bias across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken via the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”