British Law Enforcement Agencies Lobbied to Use Discriminatory Facial Recognition Systems

Police forces across the United Kingdom effectively campaigned to use a face scanning system known to be biased against women, youths, and members of minority ethnic backgrounds, following complaints that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This process entails matching a “probe image” of a person of interest against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The Home Office said it “took steps on the findings”.

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

Known Issue

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability to produce incorrect matches for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be raised to a point where the bias was greatly diminished.

However, this decision was overturned the next month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the number of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the latest NPL study found the system could produce incorrect matches for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a previously useful tool now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the conclusions of the report seriously and we have implemented changes. A updated software has been independently tested 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 protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without trained officers meticulously examining the output.”