UK Police Forces Campaign to Use Discriminatory Face Scanning Systems

Police forces across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces use the national police database to carry out searches using historical face recognition. This procedure entails comparing a “probe image” 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 system was biased. This admission came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this directive was reversed the next month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the stricter setting reduced the number of searches that yielded potential matches from over half to a just 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent independent review discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The ministry commented on these results: “The testing identified that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records note: “The change significantly reduces the impact of bias across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces argued that “a previously useful tool returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion in equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken via the equality initiative are not being translated into broader operations. Our reports have warned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson stated: “We treat the conclusions of the study with utmost gravity and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no arrest or charge would be taken without specialist personnel meticulously examining the output.”