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Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a database of over 19 million custody photos to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate biases in race and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be increased to a level where the bias was significantly reduced.

However, this decision was overturned the following month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the proportion of queries resulting in possible identifications from over half to a just 14%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the latest independent review found the system could generate false positives for Black women almost 100 times more often than for Caucasian women at certain settings.

The ministry commented on these findings: “The testing found that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that police units argued that “a once effective tactic returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month 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”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was scant discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has undertaken via the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must meet strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “We takes the findings of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will assist 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 meticulously examining the results.”