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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated fewer potential suspects.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This acknowledgment followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for overriding basic freedoms.”

Known Issue

Internal documents show that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest false positives for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the accuracy setting required for possible hits be raised to a point where the disparity was greatly diminished.

However, this directive was reversed the next month after forces complained that the adjusted system was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the proportion of searches that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the latest NPL study found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

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

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to widen the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the police race action plan, commented: “There was very little discussion through race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has made through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be pursued without specialist personnel meticulously examining the output.”