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Law enforcement agencies across the United Kingdom successfully lobbied to use a face scanning system known to be discriminatory against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry stated it “had acted on the findings”.

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

Long-Standing Problem

Internal documents show that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to address the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability to produce incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the bias was significantly reduced.

However, this directive was reversed the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold cut the proportion of queries that yielded potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest NPL study found the system could generate false positives for Black women nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these findings: “The testing identified that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a once effective tactic returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant consideration in race action plan meetings of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “We takes the conclusions of the report seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be taken without trained officers carefully reviewing the results.”