British Police Forces Campaign to Use Discriminatory Face Scanning Systems

Police forces across the UK successfully lobbied to use a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a less biased version produced a reduced number of potential suspects.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This procedure entails comparing a reference photograph of a person of interest against a database of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept discrimination in race and gender. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

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

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

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a point where the disparity was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was producing fewer “investigative leads”. Internal records show the stricter setting cut the proportion of searches resulting in possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is now in operation, the recent independent review found the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the police records state: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The documents further note that forces complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration through equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination the police has made through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “We takes the conclusions of the study seriously and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the output.”