British Law Enforcement Agencies Lobbied to Employ Biased Facial Recognition Systems

Police forces across the UK successfully lobbied to use a facial recognition system known to be discriminatory against females, young people, and members of ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This procedure involves matching a reference photograph of a suspect against a database of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers 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 system's bias in September 2024. The Home Office-commissioned 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 Policy U-Turn

In reaction, the national police leadership body ordered that the accuracy setting required for potential matches be increased to a level where the disparity was greatly diminished.

However, this decision was reversed the following month after forces complained that the modified technology was producing fewer “investigative leads”. NPCC documents show the stricter setting cut the proportion of queries that yielded possible identifications from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent NPL study found the system could generate incorrect matches 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 algorithm is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents state: “This adjustment greatly lessens the impact of bias across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “There was scant consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We treat the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be trialled in the coming months and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be taken without specialist personnel meticulously examining the results.”