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Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against women, youths, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out searches using historical face recognition. This process entails comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate biases in race and gender. Convenience is a poor argument for disregarding basic freedoms.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was more likely to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a level where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting cut the number of searches resulting in potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the latest NPL study found the system could generate incorrect matches for Black women nearly a hundred times more frequently than for Caucasian women at specific configurations.

The Home Office stated on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on police efficiency”. The documents add that forces complained that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the police race action plan, commented: “There was scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “The Home Office takes the conclusions of the report seriously and we have implemented changes. A new algorithm has been independently tested 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 ensuring public safety. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be pursued without specialist personnel meticulously examining the output.”