UK Police Forces Campaign to Use Biased Facial Recognition Systems

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

How the System Works

UK forces use the national police database to carry out searches using historical face recognition. This process entails comparing a “probe image” of a person of interest against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

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

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study found 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 reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a point where the disparity was greatly diminished.

However, this decision was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. Internal records show the higher threshold reduced the number of queries that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of bias across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a previously useful tool returned outcomes 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 “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was very little discussion through race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office takes the conclusions of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the results.”