Page "Electronic tagging" Paragraph 5

A simpler form is in regular use in the United Kingdom, where a base station is connected to the mains supply at the offender's home, and a tag is attached to the offender's ankle.

If the tag isn't functioning and within range of the base during curfew hours, or if the base is disconnected from the power supply, then the authorities are automatically alerted.

Some systems are connected to a hard wired telephone line, whilst more modern systems utilise a mobile phone / cellular system to communicate with the authorities.

The system can also be used to enforce restrictions away from specified locations such as victims ' homes, and football grounds.

Instead of allowing full location tracking, this system can be used to enforce the curfews which commonly form part of community-based sentences, the conditions of Home Detention Curfew or parole of offenders released from prison.

Most of these uses are now covered by the Criminal Justice Act 2003 in England and Wales, with separate legislation applying in Scotland.

The system is also used for monitoring those subject to house arrest or other " Control orders " under the Prevention of Terrorism Act 2005.