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

How the System Works

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 repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and women at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in race and sex. Convenience is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was producing fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries that yielded potential matches from 56% to a just 14%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest independent review discovered the system could generate incorrect matches for Black women nearly a hundred times more frequently than for white women at certain settings.

The ministry stated on these results: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, commented: “We observed very little consideration through race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the anti-racism commitments policing has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

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

Official Statement

A government representative said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. 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 evaluation.

“Our priority is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be taken without trained officers meticulously examining the results.”