🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to deploy a face scanning system acknowledged as biased against females, youths, and individuals from ethnic minority groups, after complaining that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to carry out searches using historical face recognition. This process entails comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate biases in race and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Official papers reveal that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a point where the disparity was significantly reduced.

However, this decision was overturned the next month following complaints from police that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the number of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the recent NPL study discovered the system could generate incorrect matches for Black women almost 100 times more frequently than for Caucasian women at certain settings.

The ministry stated on these results: “The testing found that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week 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 “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, commented: “There was very little discussion in race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“These revelations show once again that the pledges to combat discrimination the police has undertaken through the equality initiative are failing to be integrated into wider practice. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must meet strict national standards, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “We takes the findings of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without specialist personnel meticulously examining the output.”