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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system acknowledged as biased against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced fewer investigative leads.

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 suspect against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate discrimination in race and gender. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce 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 Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a level where the bias was greatly diminished.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “useful lines of inquiry”. Internal records show the higher threshold reduced the proportion of searches that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest independent review discovered the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The ministry stated on these results: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The papers add that forces complained that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was scant consideration through equality strategy sessions of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made through the race action plan are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office treat the conclusions of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the output.”