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Police forces across the UK successfully lobbied to deploy a facial recognition system acknowledged as discriminatory against women, youths, and individuals from ethnic minority groups, after complaining that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This procedure involves comparing a reference photograph of a person of interest against a database of more than 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate biases in race and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Police bosses were informed of the system's bias in late 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be raised to a point where the bias was greatly diminished.

However, this directive was reversed the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the higher threshold 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 currently used, the latest NPL study discovered the system could generate incorrect matches for women of Black heritage almost 100 times more often than for white women at certain settings.

The ministry stated on these findings: “The testing identified that in a limited set of circumstances the software 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 police records state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The papers add that forces argued that “a previously useful tool now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “There was very little consideration through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments the police has made through the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A government representative said: “We treat the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”