British Police Forces Lobbied to Employ Discriminatory Face Scanning Systems

Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be discriminatory against females, youths, and members of minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This process entails matching a reference photograph of a suspect against a repository of over 19 million mugshots to find possible hits.

Admitted Bias

The Home Office admitted last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users accept biases in race and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce incorrect matches for photos of females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a level where the disparity was greatly diminished.

However, this decision was overturned the following month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of queries that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the latest NPL study found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these results: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units argued that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration 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 labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “There was scant discussion through race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A government representative said: “We takes the conclusions of the report seriously 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 gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”