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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as biased against women, young people, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated fewer investigative leads.

The Technology in Practice

British police use the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission came after a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in race and sex. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest false positives for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the disparity was greatly diminished.

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

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest independent review discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, 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 now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals 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, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little consideration through race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments policing has undertaken through the race action plan are not being translated into broader operations. Our reports have warned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes 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 demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“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 each stage of the procedure and no arrest or charge would be pursued without specialist personnel meticulously examining the results.”