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Police forces across the UK successfully lobbied to deploy a facial recognition system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a less biased version produced fewer potential suspects.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Admitted Bias

The Home Office admitted last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was more likely to produce incorrect matches 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 accuracy setting required for possible hits be increased to a level where the bias was greatly diminished.

However, this decision was reversed the next month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the number of queries that yielded possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

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

Operational Effectiveness vs. Bias

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

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “We observed scant consideration through equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into wider practice. Our reports have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A government representative stated: “The Home Office treat the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to 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 process and no further action would be pursued without trained officers carefully reviewing the results.”