British Law Enforcement Agencies Lobbied to Employ Biased Face Scanning Systems

Police forces across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as biased against women, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. 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 ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users accept biases in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for photos of women, Black people, 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 point where the bias was significantly reduced.

However, this directive was reversed the next month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the number of searches resulting in potential matches from 56% to a mere 14%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the latest independent review discovered the system could generate incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the police records state: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion through race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination policing has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

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

Official Statement

A government representative said: “We takes the findings of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without specialist personnel carefully reviewing the results.”