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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This procedure entails matching a reference photograph of a suspect against a database of over 19 million custody photos to find potential matches.

Admitted Bias

The Home Office conceded last week that the system was biased. This acknowledgment followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The Home Office said it “had acted 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 poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered laboratory study found the system was had a higher probability to produce incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

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 reversed the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records indicate the higher threshold reduced the number of searches resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

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

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

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents state: “The change significantly reduces the effect of discrimination across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents further note that forces argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was very little consideration in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

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

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested 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 officers 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 output.”