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Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against females, young people, and members of ethnic minority groups, following complaints that a less biased version generated fewer investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This procedure involves matching a reference photograph of a suspect against a database of more than 19 million custody photos to find possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This acknowledgment came after a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The Home Office stated 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. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been known about 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 algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to produce false positives for photos of women, Black people, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the number of queries resulting in potential matches from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study found the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The Home Office commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records note: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The documents add that police units argued that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month consultation on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has made through the equality initiative are not being translated into wider practice. Our reports have warned 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 meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A government representative said: “We treat the findings 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.

“Our priority is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no further action would be pursued without specialist personnel carefully reviewing the results.”