UK Police Forces Campaign to Employ Biased Facial Recognition Systems

Police forces across the UK successfully lobbied to deploy a face scanning system acknowledged as discriminatory against females, young people, and members of ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a suspect against a repository of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in race and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this bias has been known about for over twelve months. Furthermore, police forces 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 government-ordered NPL review concluded the system was had a higher probability to produce false positives for photos of females, 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 possible hits be raised to a point where the bias was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was producing fewer “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries that yielded potential matches from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent independent review discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the police records note: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The papers add that forces argued that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “biggest breakthrough 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: “We observed scant discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has made through the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A new algorithm 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.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the results.”