🔗 Share this article

Police forces across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the national police database to carry out searches using historical face recognition. This process involves matching a reference photograph of a suspect against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users tolerate biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was more likely to produce false positives for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

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 decision was overturned the following month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the higher threshold reduced the number of queries resulting in potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the latest 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: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration through equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations show once again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have warned that innovative tools are being rolled out in a context 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 demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “We takes the conclusions of the study seriously and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

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