Met police to use Live Facial Recognition cameras in crackdown on crime

The Metropolitan Police are to push ahead with live facial recognition cameras as a new tool following a research study by experts at Teddington's National Physical Laboratory. (NPL)

The decision follows the publication today - Thursday – of what the Met calls ground-breaking research by NPL into the use and accuracy of the tech.

The technology involves using cameras mounted on police vehicles, which scan crowds and streets to see if any faces match a predetermined watchlist and then generate an alert.

Some retailers use these systems to identify known shoplifters if they enter a store, which sends an alert to shop staff and a central security hub. Credit: Metropolitan Police.

Some retailers use these systems to identify known shoplifters if they enter a store, which sends an alert to shop staff and a central security hub.

However, the move to push ahead with Live Facial Recognition (LFR) is controversial. Last year, academics at Cambridge University recommended a ban on its use in all public spaces.

A team from the Minderoo Centre for Technology and Democracy argued it was unreliable, and broke both ethical standards and human rights laws.

However, the Met argues that accuracy concerns have been overcome as a result of the NPL research.

NPL laboratories, Teddington. Credit: NPL.

The study, 'Facial Recognition Technology in Law Enforcement' tested the accuracy, in operational conditions, of the algorithm used by the Met in terms of different demographics – in terms of race, age and gender.

In the past, there have been concerns that the technology will create false alerts, for example there were more false positives for people with dark skin with the overall false positive rate of 1 in 1,000.

The Met said the new research shows that it is possible to refine the algorithm of the cameras and technology to require a high level match before an alert is raised.

It said: "We now better understand the demographic performance of our LFR system. At the setting we have been using it, there is no statistically significant bias in relation to race and gender and the chance of a false match is just 1 in 6000 people who pass the camera."

The NPL research, which was led by Principal Research Scientist, Dr Tony Mansfield, found the most accurate results were for Asian females while the least accurate were for black females, however this was not statistically significant.

Accuracy for young people was lower than for those over 42, although researchers said the test results may have been influenced by factors such as how crowded an area was.

Lindsey Chiswick, Director of Intelligence for the Met said: "Live Facial Recognition technology is a precise community crime fighting tool. Led by intelligence, we place our effort where it is likely to have the greatest effect. It enables us to be more focused in our approach to tackle crime, including robbery and violence against women and girls.

"This is a significant report for policing, as it is the first time we have had independent scientific evidence to advise us on the accuracy and any demographic differences of our Facial Recognition Technology.

"We commissioned the work so we could get a better understanding of our facial recognition technology, and this scientific analysis has given us a greater insight into its performance for future deployments.

"We know that at the setting we have been using it, the performance is the same across race and gender and the chance of a false match is just 1 in 6000 people who pass the camera. All matches are manually reviewed by an officer. If the officer thinks it is a match, a conversation will follow to check.

"The study was large enough to ensure any demographic differences would be seen. However, he has also been able to extrapolate these figures to reflect results more representative of watch list size for previous LFR deployments."

She added: "We understand the concerns raised by some groups and individuals about emerging technology and the potential for bias.

"We have listened to these voices. This research means we better understand the performance of our algorithm. We understand how we can operate to ensure the performance across race and gender is equal."

NPL stressed it is an independent scientific research organisation and does not offer any endorsements.

It said: "NPL has conducted a study of the accuracy and equitability of the Metropolitan Police Service's facial recognition applications. This study has been running since May 2022 and was undertaken to determine the performance of the system and whether there is equitable performance across demographics.

"In this case NPL were asked to assess the performance of facial recognition technology in an operational setting, in terms of accuracy and equitability related to subject demographics and assess the data outputs from this. This work was conducted to provide the Metropolitan Police with an understanding of how their facial recognition algorithms perform.

"As an independent and impartial National Laboratory, NPL neither endorses products tested nor recommends how products should be used."