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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against women, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the system was biased. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. 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 gender. Convenience is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was more likely to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. Internal records show the higher threshold cut the number of searches that yielded possible identifications from over half to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest independent review found the system could produce false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry stated on these findings: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces complained that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “We observed scant discussion in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has undertaken through the race action plan are not being translated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “We treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without trained officers carefully reviewing the results.”