UK Law Enforcement Agencies Lobbied to Employ Biased Face Scanning Systems

Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated fewer potential suspects.

The Technology in Practice

UK forces use the national police database to carry out searches using historical face recognition. This procedure involves matching a reference photograph of a suspect against a database of over 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

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

Long-Standing Problem

Official papers reveal that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a level where the disparity was significantly reduced.

However, this directive was overturned the next month following complaints from police that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the proportion of queries that yielded possible identifications from 56% to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the recent independent review discovered the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “The change greatly lessens the effect of bias across protected characteristics of ethnicity, age and sex but had a significant negative impact on operational effectiveness”. The papers add that police units argued that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to expand the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, said: “There was very little consideration in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made through the race action plan are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

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

Home Office Response

A government representative said: “We takes the conclusions 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 tested early next year and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”