British Law Enforcement Agencies Campaign to Use Biased Facial Recognition Systems

Police forces across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against females, young people, and members of ethnic minority groups, following complaints that a more accurate version generated a reduced number of potential suspects.

How the System Works

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process entails matching a “probe image” of a suspect against a repository of over 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission came after a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The Home Office stated it “took steps on the findings”.

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

Known Issue

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was more likely to produce false positives for photos of women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. Internal records show the higher threshold reduced the number of queries resulting in potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the latest NPL study discovered the system could produce false positives for Black women nearly a hundred times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these results: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the effect of bias across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces complained that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister Sarah Jones has described 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 independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration through race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into wider practice. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson said: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been independently tested 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 protecting the public. This revolutionary tool will support police to put criminals and rapists behind bars. There is officer review in each stage of the process and no arrest or charge would be pursued without trained officers meticulously examining the results.”