British Police Forces Lobbied to Employ Biased Face Scanning Systems

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

The Technology in Practice

British police utilize the national police database to carry out retrospective facial recognition searches. This procedure involves comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to find possible hits.

Admitted Bias

The Home Office conceded last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision 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 more likely to produce false positives for photos of females, Black people, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a level where the bias was significantly reduced.

However, this decision was overturned the following month following complaints from police that the modified technology was generating fewer “investigative leads”. Internal records show the higher threshold reduced the number of searches resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the latest independent review found the system could generate incorrect matches for Black women almost 100 times more often than for white women at certain settings.

The Home Office stated on these results: “The testing found that in a specific scenarios the software is more likely to wrongly flag 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 greatly lessens the effect of bias across protected characteristics of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a once effective tactic returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans 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”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little discussion in equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the pledges to combat discrimination the police has made via the equality initiative are failing to be integrated into broader operations. Our reports have warned 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 this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A government representative stated: “We takes the conclusions of the report 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 tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be pursued without trained officers meticulously examining the output.”