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Police forces across the UK successfully lobbied to deploy a face scanning system known to be biased against women, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated fewer investigative leads.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This process involves matching a reference photograph of a person of interest against a database of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate biases in ethnicity and sex. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce false positives for photos of women, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a point where the bias was greatly diminished.

However, this directive was reversed the following month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of searches resulting in possible identifications from 56% to a just under 15%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the recent NPL study found the system could generate false positives for Black women almost 100 times more often than for white women at certain settings.

The Home Office commented on these results: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the impact of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed scant discussion through equality strategy sessions of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has undertaken via the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the results.”