UK Law Enforcement Agencies Lobbied to Employ Discriminatory Facial Recognition Systems

Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a suspect against a repository of over 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 review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“It prompts the question of whether this technology only becomes effective if users accept discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to address the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the confidence threshold required for potential matches be raised to a point where the bias was significantly reduced.

However, this decision was overturned the following month after forces complained that the modified technology was producing fewer “investigative leads”. Internal records show the higher threshold cut the proportion of queries resulting in possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the recent NPL study found the system could produce false positives for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The Home Office stated on these findings: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to widen the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head 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 facial recognition rollout despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the anti-racism commitments policing has made through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “We treat the conclusions of the study seriously 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 protecting the public. This gamechanging technology will assist police to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without trained officers meticulously examining the output.”