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Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against females, youths, and members of ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct searches using historical face recognition. This procedure involves comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment followed a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

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

Long-Standing Problem

Internal documents reveal that this bias 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 algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce false positives for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised 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 fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of queries that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent NPL study found the system could generate incorrect matches for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office stated on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's accuracy setting, the police records state: “This adjustment significantly reduces the effect of bias across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces argued that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little consideration in equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no further action would be pursued without specialist personnel carefully reviewing the output.”