Satellite tracking for criminals
Thursday, 2 September, 2004, 00:28 GMT 01:28 UK
It is the first time a European country has used satellites to monitor the movements of offenders.
Convicted burglars, robbers and car thieves will be fitted with an electronic device that can be tracked by satellite 24 hours a day.
The trials are in Greater Manchester, West Midlands and Hampshire.
The electronic device will be monitored by a control station which records the location of the offender to within a few metres.
If the offender strays into an area they are excluded from the police are alerted.
The system will also be used to prevent sex offenders going to playgrounds and schools and to stop people convicted of domestic violence from approaching their victims.
Offenders will be required to wear the device as part of a community sentence, or as a condition of their release from prison.
Initially, the system will be used to track up to 120 offenders at any one time, but if the technology works, the Home Office will use it to monitor the 5,000 most prolific offenders in England and Wales.
Home Secretary David Blunkett will launch the trials in Greater Manchester with correctional services minister Paul Goggins at the monitoring centre.
Mr Blunkett has earlier called the scheme a "prison without bars".
The electronic tagging which the government currently relies on is only able to set off an alarm when the offender breaches a curfew.
If a criminal walks out of the house after their curfew an alarm will sound at a central control room, where operators then notify police.
However, under this system there is no way of knowing where the criminal has gone.