Update July 2019

The Met’s trial of the use of Live Facial Recognition (LFR) technology has come to an end. A total of ten trials were carried out in public across London. We will now consider all information available before coming to any decision on how the technology may be used by the Met in the future.

What is Live Facial Recognition?

Live Facial Recognition (LFR), is technology that can identify a person from a digital image. The technology is being used to assist in the prevention and detection of crime by identifying wanted criminals.

The LFR cameras are focused on an area, when people pass through the area their images are streamed directly to the Live Facial Recognition system database. This database contains the ‘watch list’: a list of offenders wanted by the police and courts for various offences.

facial-recognition- 02- 1024

How the system works

Live Facial Recognition uses NEC’s NeoFace technology to analyse images of the faces of people on the watch list. It measures the structure of each face, including distance between eyes, nose, mouth and jaw to create facial data.

The system detects a face, creates a digital version of it and searches it against the watch list; where it makes a match it sends an alert to an officer on the scene.

The officer compares the camera image and the watch list image and decides whether to stop and speak to the person. We always explain why we’ve stopped someone; we also give them a leaflet that explains how they can contact us to ask any questions afterwards.

The system will only keep faces matching the watch list, these are kept for 30 days, all others are deleted immediately. We delete all other data on the watch list and the footage we record.

Anyone can refuse to be scanned; it's not an offence or considered ‘obstruction’ to actively avoid being scanned. 

How we’re using facial recognition

The Met has completed a trial of the Live Facial Recognition technology to find out if it's a useful policing tactic to deter and prevent crime and bring to justice wanted criminals. It was tested in a range of environments including public events and crowded public spaces.

Wherever we’ve used it, we’ve done so openly. That means:

  • information leaflets handed out to the public
  • posters placed in and around the area to make people aware the technology is being used
  • officers engaging with members of the public to explain the process
facial-recognition-image- 3- 1024

How the law lets us use facial recognition

The laws and legislation below allows us to use facial recognition in the way we’ve described above:

The way we use it is monitored and regulated by:

We're concerned that what we do conforms to the law, but also takes into account ethical concerns and respects human rights. These documents detail how we're doing that:


Some common terms used when talking about LFR

We're working with regulators and key stakeholders to define the terms used. Here are some of those terms:

Watch list: The 'watch list' is made up of images of people who have been taken into police custody. 

Alert: the message sent to an officer from the system to let them know that an image caught on the cameras has matched someone on the watch list.

LFR: Live Facial Recognition.

Retention: the amount of time we keep data for and how we keep it.

Signage: the posters we put up outside of the area being scanned by the cameras. We put these up before the cameras are active.