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Law enforcement agencies across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated fewer potential suspects.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This procedure involves matching a “probe image” of a person of interest against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate biases in race and sex. Convenience is a weak argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

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

However, this directive was reversed the following month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents show the higher threshold reduced the proportion of searches resulting in potential matches from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the recent NPL study found the system could produce false positives for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The ministry stated on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the impact of bias across protected characteristics of race, age and gender but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations show once again that the anti-racism commitments policing has made via the race action plan are not being translated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be pursued without trained officers meticulously examining the results.”