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Police forces across the UK effectively campaigned to deploy a facial recognition 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.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in race and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review concluded the system was more likely to produce false positives for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the disparity was significantly reduced.

However, this decision was reversed the next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold reduced the proportion of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry stated on these results: “Our evaluation found that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the police records note: “This adjustment significantly reduces the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The documents further note that forces argued that “a previously useful tool returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

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

Home Office Response

A Home Office spokesperson stated: “We takes the conclusions of the study seriously and we have already taken action. A new algorithm 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 gamechanging technology will support police to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel meticulously examining the results.”