UK Law Enforcement Agencies Campaign to Employ Discriminatory Face Scanning Systems

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

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and sex. Convenience is a weak argument for disregarding fundamental rights.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers 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 incorrect matches for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a level where the disparity was greatly diminished.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. Internal records indicate the stricter setting cut the number of searches that yielded possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent independent review found the system could generate false positives for Black women nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of bias across protected characteristics of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month 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 genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, commented: “There was very little consideration through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has made through the race action plan are not being translated into wider practice. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be pursued without specialist personnel meticulously examining the results.”