We use Live Facial Recognition to help tackle serious violence, gun and knife crime, child sexual exploitation and help protect the vulnerable.

What is Live Facial Recognition?

Live Facial Recognition (LFR) is technology that can help locate a person from a digital image. We're using this technology to prevent and detect crime by helping officers find wanted criminals.

LFR cameras are focused on an area; when people pass through the area their images are streamed directly to the live facial recognition system. This system contains a ‘watchlist’: a list of offenders wanted by the police or the courts, or those who pose a risk of harm to themselves or others.

How the system works

The Met currently uses NEC’s NeoFace Live Facial Recognition technology to take images and compare them to images of people on the watchlist. It measures the structure of each face, including distance between eyes, nose, mouth and jaw to create a facial template.

Where it finds a match it sends an alert to officers on the scene.

An officer then compares the camera image to the person they see and decides whether to speak to the person or not. 

We always explain why we’ve stopped someone; we also give them a leaflet that explains how they can contact us to ask further questions.

The system will only keep images that have generated an alert, these are kept for up to 31 days or, if an arrest is made, until any investigation or judicial process is concluded.

The biometric data of those who don't cause an alert is automatically and immediately deleted. The LFR system also records CCTV footage, we keep that footage for up to 31 days.

Anyone can decide not to walk past the LFR system; it's not an offence or considered ‘obstruction’ to avoid it. 

How we’re using facial recognition

We completed ten trials using Live Facial Recognition technology to find out if it was a useful policing tactic to deter and prevent crime and bring wanted criminals to justice.

It was tested in a range of environments including public events and crowded public spaces. It will now be used to aid policing operations where we have intelligence that supports its use.

Wherever we use it, we’ll do so openly. That means we'll:

  • tell people online where we're going to use LFR before any deployment
  • publish the results of each deployment on the Met website
  • provide information leaflets to give to the public
  • place posters and signs in and around the area to make people aware the technology is being used
  • make officers available to talk to members of the public to help explain what's happening and how LFR works

The Met is considering updating the technology used for Retrospective Facial Recognition where we compare CCTV or other images against the custody image database in order to help identify unknown suspects. As part of this process we are intending to speak to the technology sector to explore the current options that may be available.

What is Retrospective Facial Technology?

Retrospective Facial Recognition is a technology that can assist the Metropolitan Police in identifying an unknown suspect from a CCTV or other image that has come to light as part of a criminal investigation. The technology is used to check if the image matches any of the photos that we hold of people who have previously come into police custody. Any “match” identified by the technology is manually reviewed before police officers decide on the next stages.

How the law lets us use facial recognition

These laws and legislation allow us to use facial recognition in the way we’ve described:

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

The PDF(s) on this page may not be suitable for users of assistive technology. We are in the process of updating them, but please email us to request an accessible version. See our accessibility statement.

Court of Appeal judgment

The Met is aware that the Court of Appeal has made its judgment regarding specific concerns raised about the use of South Wales Police facial recognition technology.

The Met's approach to live facial recognition is different to the South Wales Police cases which were appealed.

This reflects our policing needs, which given the complexity of keeping London safe and the different crime issues impacting the capital, are very different from those in South Wales. Differences include that the Met has been clear that our use of this technology is intelligence-led, and focused on helping tackle serious crime, including serious violence, gun and knife crime, child sexual exploitation and helping protect the vulnerable. We tell the public about each use of facial recognition technology in advance of, during and afterwards.

We use the latest accurate algorithm and have our own tailored and carefully considered policy documents. This is reflective of the Met’s use of live facial recognition (LFR) to keep Londoners safe.

We will carefully consider the judgment and act on any relevant points to ensure that we maintain our commitment to use facial recognition in a legal, ethical and proportionate way.