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The Electronic Monitoring of Adult Offenders

According to the National Audit Office, electronic monitoring of adult offenders provides value for money and a cost effective alternative to custody for low risk offenders. Three months of an electronically monitored curfew are nearly five times cheaper than three months in custody. On average, it costs £1,300 to monitor an offender who has been released from prison on Home Detention Curfew for 90 days compared to £6,500 for the same period in custody. In addition, the use of Home Detention Curfew has reduced pressure on the prison population. NAO testing of the technology used for electronic monitoring showed that it is robust and reliable, detecting absences during curfew periods plus attempts to cut off the tag or tamper with the equipment.

Today’s report to Parliament by the head of the NAO, Sir John Bourn, highlights the number of agencies involved in electronic monitoring, and difficulties they sometimes have communicating with each other and the private contractors who provide the equipment and who actually monitor offenders. The Probation Service, the courts and prisons assess whether an offender is suitable for an electronically monitored curfew and the contractors fit the equipment and monitor the offender. If the offender breaches his or her curfew, courts, prisons, police and the Home Office can be involved in returning the offender to either prison or court. For electronic monitoring to be most effective, co-ordination across the criminal justice system needs to be improved. This will reduce the risk of delays in fitting tags or reporting breaches of curfew and will also make the assessment of offenders more efficient.

The cost of electronic monitoring has fallen considerably since new contracts began in April 2005. The National Offender Management Service could make further savings of up to £9 million a year if it streamlined its assessment process. At present, delays mean that only 59 per cent of the prisoners assessed as suitable for Home Detention Curfew are released as soon as they are eligible. Delays occur because prison governors are waiting for reports from probation or other prisons or for the offender’s criminal record.

The impact of the curfew is undermined if the equipment is not installed on time, or if breaches are not promptly dealt with. Of the 290 cases examined, 90 per cent of curfewees were fitted with a tag within 24 hours of the start of their curfew. Delays were caused by the offender themselves, by late or inaccurate information being sent by prisons and courts, and problems setting up the equipment or getting a telephone line installed.

62 cases of these cases related to the first two months of the new contracts (April and May 2005). The NAO found that only 85 per cent of offenders in these cases were tagged on time, although this performance has since improved. Of the 78 cases examined where Home Detention Curfew had been breached, 35 per cent were not reported to the Home Office by the contractors within 24 hours. The NAO also examined a small sample of 35 cases where Curfew Orders had been breached and found that the contractors had reported only 31 per cent to the courts on time. Such delays can be damaging as the offender may not be electronically monitored during this period (if, for example, he or she has cut the tag off) which increases the risk of further breaches or re-offending. Long delays between a breach and an offender either being returned to court or to prison may also create the impression that offenders can breach with impunity, reducing public confidence in the criminal justice system.

Most of the offenders interviewed for the report believed that being on an electronically monitored curfew had been positive, allowing then to remain with their families and to seek employment, and preventing them slipping back into a criminal routine. Our data suggests that curfewees are less likely to re-offend than offenders in custody or on other community penalties, although further research is required to establish this link.

"Electronic monitoring represents value for money, providing a cost-effective alternative to custody for offenders who do not pose a risk to the public. However, to ensure that a curfew is effective, it is essential that the contractors and criminal justice agencies work together to ensure that offenders are always tagged promptly and that any breaches of their curfew are dealt with quickly.”

Sir John Bourn, 1 February 2006

Notes for Editors

  1. The National Offender Management Service (NOMS), part of the Home Office, was established in June 2004 to bring together the Prison Service and the National Probation Service. The Service will introduce end-to-end offender management with the aim of reducing re-offending.
  2. Contracts for electronic monitoring are let by the Electronic Monitoring Team within NOMS. They were re-tendered in 2004, and new contracts with Securicor Justice Services and Serco Home Affairs began on 1 April 2005. Securicor Justice Services covers the North East and North West; East Midlands, Yorkshire and Humberside; and the South East and South West. Serco Home Affairs covers London, Eastern England, Wales and the West Midlands. Electronic monitoring in Scotland is the responsibility of the Scottish Executive and it is not used in Northern Ireland.
  3. Curfewees are fitted with an electronic tag around their ankle, which sends a regular signal to a receiver unit installed in their home. The receiving unit is connected to a telephone line and informs the monitoring agencies if the curfewee is not there during curfew hours, or if he or she tampers with either the tag or the receiving unit.
  4. Electronic monitoring was piloted for adult defendants on bail from 1989 to 1990, for adult offenders sentenced to a curfew order from 1995 to 1999, and for adult and juvenile defendants on bail, juvenile offenders sentenced to a curfew order by a court, and fine defaulters and persistent petty offenders, from 1998 to 2000. It was rolled out to the whole of England and Wales in 1999 for the two categories of adult offenders who are the subject of this report.
  5. In relation to these offenders, electronic monitoring is used in two ways: to monitor compliance with Home Detention Curfew (HDC) and Curfew Orders. Home Detention Curfew is granted to offenders serving primarily between three months and under four years in prison, if the governor is satisfied that they are not a risk to the public. Sex offenders and dangerous violent offenders are not eligible. Curfews usually run for 12 hours overnight. It aims to provide structure to the lives of offenders, aiding the transition from prison to life in the community, allowing offenders to work and remain with their families whilst serving their sentence, and also reducing the pressure on the prison population. Curfew Orders are a sentence of the court, which are used for offenders aged 16 or over, and last between 2 and 12 hours a day. Electronically monitored curfews are also currently used for young offenders, adult and juvenile defendants on bail and small numbers of asylum seekers.
  6. Press notices and reports are available from the date of publication on the National Audit Office website at Hard copies can be obtained from The Stationery Office on 0845 7023474
  7. The Comptroller and Auditor General, Sir John Bourn, is the head of the National Audit Office which employs some 800 staff. He and the National Audit Office are totally independent of Government. He certifies the accounts of all Government departments and a wide range of other public sector bodies; and he has statutory authority to report to Parliament on the economy, efficiency and effectiveness with which departments and other bodies have used their resources.


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PN: 8/06