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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, following complaints that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The government-ordered laboratory study found the system was had a higher probability to suggest incorrect matches for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be raised to a level where the disparity was greatly diminished.

However, this directive was overturned the next month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the higher threshold reduced the number of searches resulting in possible identifications from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of bias across protected characteristics of race, generation and gender but had a significant negative impact on police efficiency”. The documents further note that police units argued that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “We observed very little discussion through race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has undertaken through the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the study seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

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