Electronic monitoring

A cost effective compliance solution for subjects at home or in the community using a variety of proven technologies and applications.



We are the world’s largest provider of electronic monitoring services, monitoring over 40,000 subjects.

We provide a comprehensive range of services that support the work of Criminal Justice and Immigration agencies across the world.

In the UK alone G4S monitors over 11,500 subjects. We are responsible for providing electronic monitoring services within three contract areas as follows:
We also monitor subjects on behalf of the UK Border Agency (UKBA) either through electronically monitored curfews or voice verification.


What is an electronically monitored curfew?


When a person is under curfew they must stay at home (or other specified place) during certain hours. This is usually for 12 hours during a 24 hour period, every day of the week. The hours can vary depending on circumstances, but most curfews are at night.

G4S checks that people are keeping to their curfew. We do this electronically using a tag and a monitoring unit.

Curfews are used throughout the criminal justice system (as a community service condition of bail or as a condition of release from prison) and also by the UK Borders Agency and Nationality Directorate.


How do we monitor subjects?


Using the latest technology we can monitor subjects through:
Read more about our technology.


Working in Partnership


We work closely with both the Ministry of Justice and UKBA in managing these contracts but also work closely with agencies such as:
Our Relationship Management Team work with stakeholders to provide a greater undertsanding of our technology and the applications of electronic monitoring. Contact our Relationship Management Team on 0161 862 1000 or email em.comms@uk.g4s.com, see their contact informtion for local contacts.