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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against females, young people, and individuals from ethnic minority groups, following complaints that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the national police database to conduct searches using historical face recognition. This process entails matching a reference photograph of a suspect against a database of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was flawed. This acknowledgment came after a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The ministry said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users tolerate biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study 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 response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the adjusted system was producing fewer “investigative leads”. Internal records show the higher threshold cut the proportion of searches resulting in potential matches from 56% to a just under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent independent review discovered the system could generate false positives for Black women almost 100 times more frequently than for white women at certain settings.

The ministry commented on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The papers further note that police units complained that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration in equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the anti-racism commitments the police has undertaken through the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “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 demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the results.”