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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This process involves matching a reference photograph of a suspect against a database of more than 19 million mugshots to find possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission came after a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The government-ordered laboratory study concluded the system was more likely to suggest incorrect matches 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 potential matches be increased to a level where the bias was significantly reduced.

However, this decision was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of searches that yielded possible identifications from 56% to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest independent review found the system could produce incorrect matches for Black women almost 100 times more often than for white women at certain settings.

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

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“These revelations show once again that the pledges to combat discrimination policing has undertaken through the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“Our priority is ensuring public safety. This gamechanging technology will support police to put criminals and rapists behind bars. There is human involvement in every step of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”