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Police forces across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of potential suspects.

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 repository of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in ethnicity and gender. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

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

Senior officers were notified of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this directive was reversed the next month following complaints from police that the adjusted system was producing a lower number of “investigative leads”. Internal records show the higher threshold cut the proportion of queries resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent NPL study found the system could generate incorrect matches for Black women nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these results: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “There was very little discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made through the equality initiative are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the findings of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”