British Law Enforcement Agencies Lobbied to Use Discriminatory Facial Recognition Systems

Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system known to be biased against females, young people, and members of minority ethnic backgrounds, after complaining that a less biased version generated fewer potential suspects.

How the System Works

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a suspect against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment followed a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be raised to a level where the bias was greatly diminished.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. NPCC documents show the stricter setting reduced the number of searches that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is now in operation, the latest independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these results: “The testing identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “The change significantly reduces the effect of bias across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units argued that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

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

“This disclosure show once again that the anti-racism commitments the police has made via the equality initiative are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”