British Police Forces Campaign to Employ Discriminatory Facial Recognition Technology

Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be discriminatory against women, youths, and members of ethnic minority groups, following complaints that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

British police utilize the national police database to carry out retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission followed a study by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and women at much greater frequency than Caucasian males. The ministry 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. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review concluded the system was more likely to produce incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be increased to a level where the disparity was significantly reduced.

However, this decision was reversed the following month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the proportion of queries that yielded possible identifications from over half to a mere 14%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the latest NPL study discovered the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The Home Office stated on these results: “The testing found that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “biggest breakthrough 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 police race action plan, commented: “We observed very little discussion in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has undertaken via the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being implemented in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “We takes the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be pursued without specialist personnel meticulously examining the output.”