British Law Enforcement Agencies Campaign to Employ Biased Face Scanning Technology

Police forces across the UK successfully lobbied to deploy a facial recognition system known to be biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of potential suspects.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This procedure entails matching a reference photograph of a suspect against a repository of over 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office admitted last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at significantly higher rates than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users accept discrimination in race and sex. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased 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 a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the proportion of searches that yielded possible identifications from over half 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 produce incorrect matches for Black women nearly a hundred times more frequently than for white women at certain settings.

The ministry commented on these results: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the police records note: “The change greatly lessens the effect of bias across legally safeguarded attributes of race, age and gender but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a once effective tactic returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has described the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration through equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into wider practice. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

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

Official Statement

A Home Office spokesperson said: “The Home Office treat the conclusions of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be taken without trained officers meticulously examining the output.”