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Police forces across the United Kingdom effectively campaigned to use a face scanning system known to be biased against women, youths, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of potential suspects.

How the System Works

British police use the national police database to carry out searches using historical face recognition. This process entails 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 technology was flawed. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers show that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study found the system was had a higher probability to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the number of searches that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what threshold is now in operation, the latest NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The Home Office commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “The change greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The documents further note that police units argued that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “There was scant discussion through equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken through the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to strict national standards, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “We takes the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no further action would be pursued without trained officers carefully reviewing the results.”