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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against women, young people, and members of ethnic minority groups, after complaining that a more accurate version generated fewer investigative leads.

How the System Works

UK forces utilize the national police database to conduct retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a repository of more than 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry conceded 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 Home Office said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a point where the bias was significantly reduced.

However, this directive was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of queries that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the effect of discrimination across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough 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: “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 yet again that the anti-racism commitments the police has undertaken through the equality initiative are not being translated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative said: “The Home Office takes the findings of the study 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 tested in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool 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 carefully reviewing the output.”