🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system known to be biased against females, young people, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated fewer investigative leads.

How the System Works

British police utilize the national police database to carry out searches using historical face recognition. This process entails comparing a “probe image” of a suspect against a database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage 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 this technology only becomes effective if users accept biases in race 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 over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to suggest false positives 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 accuracy setting required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of searches resulting in potential matches from 56% to a mere under 15%.

Profound Inequalities

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

The Home Office stated on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units complained that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little consideration in race action plan meetings 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 broader operations. Our reports have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “The Home Office treat the conclusions of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no arrest or charge would be taken without trained officers meticulously examining the results.”