British Police Forces Lobbied to Employ Discriminatory Face Scanning Technology

Police forces across the UK successfully lobbied to use a face scanning system known to be biased against women, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

British police utilize the national police database to carry out searches using historical face recognition. This procedure involves comparing a “probe image” of a person of interest against a database of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

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

“This raises the question of whether this technology only becomes effective if users tolerate biases in ethnicity and sex. Operational ease is a poor argument for overriding basic freedoms.”

Known Issue

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 mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce false positives for images depicting females, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body mandated that the accuracy setting required for potential matches be raised to a point where the disparity was greatly diminished.

However, this directive was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. Internal records show the higher threshold cut the proportion of searches resulting in potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study discovered the system could produce incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The Home Office stated on these findings: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's accuracy setting, the police records state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has made via the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative said: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no further action would be pursued without specialist personnel carefully reviewing the output.”