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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system known to be discriminatory against females, young people, and members of minority ethnic backgrounds, following complaints that a less biased version generated a reduced number of investigative leads.

How the System Works

UK forces utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users accept biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Official papers show that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

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

However, this directive was reversed the following month following complaints from police that the modified technology was generating a lower number of “investigative leads”. Internal records show the stricter setting cut the proportion of queries that yielded potential matches from 56% to a mere 14%.

Severe Disparities

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

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

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation 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

Abimbola Johnson, chair 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 even with clear relevance with the plan’s concerns.

“These revelations 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 new technologies are being implemented in a context where racial disparities, inadequate oversight 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 diminishes rather than exacerbates ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat the conclusions of the report seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be taken without trained officers carefully reviewing the results.”