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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system known to be discriminatory against women, youths, and individuals from ethnic minority groups, after complaining that a more accurate version generated fewer potential suspects.

The Technology in Practice

UK forces use the national police database to conduct searches using historical face recognition. This process involves comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify possible hits.

Admitted Bias

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

“It prompts the issue of whether this technology only becomes useful if users accept biases in race and gender. Convenience is a poor argument for disregarding fundamental rights.”

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.

Police bosses were informed of the system's bias in late 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest incorrect matches for images depicting women, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be increased to a level where the bias was greatly diminished.

However, this directive was overturned the next month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents indicate the stricter setting reduced the proportion of queries resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest independent review found the system could produce false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones 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 equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has made via the equality initiative are failing to be integrated into wider practice. Our reports have warned 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 adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson said: “We treat the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and procured, 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 assist officers to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be pursued without trained officers carefully reviewing the results.”