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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of potential suspects.

How the System Works

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the question of whether facial recognition only becomes useful if users accept discrimination in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was more likely to suggest incorrect matches for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

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

However, this directive was overturned the next month following complaints from police that the modified technology was producing a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the number of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the software is more likely to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age 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 outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant consideration through race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments policing has undertaken through the equality initiative are not being translated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the conclusions of the study seriously and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be pursued without trained officers carefully reviewing the results.”