Legal background
Sentences of imprisonment are generally served part in prison and part in the community. Under current legislation, prisoners in England and Wales must be released in accordance with the provisions contained in the Criminal Justice Act 2003 ("the 2003 Act") and the legacy release provisions of the Criminal Justice Act 1991 which are restated in Schedule 20B of the 2003 Act. In Scotland, prisoners must be released in accordance with the terms of the 1993 Act.
	The following fixed-term sentences (which are explained further below) attract automatic release or a right of consideration for release by the Parole Board at the halfway or two-thirds point:
Standard Determinate Sentences (SDS) where the prisoner is released automatically at the halfway point on licence.
In Scotland short-term custodial sentences (under four years) which have automatic release at the halfway point and long-term sentences (four years and above) which have discretionary release from the halfway point.
Sentence for Offenders of Particular Concern (SOPC) (England and Wales only) where the prisoner is eligible to be considered for release by the Parole Board at the halfway point of the custodial term.
Extended Determinate Sentences (EDS) where, as initially enacted in 2012, some prisoners were subject to automatic release at the two-thirds point of the custodial term (since 2015, the EDS was amended to provide for discretionary release by the Parole Board between two-thirds and end points for all EDSs imposed).
Extended Sentences (in Scotland) where the prisoner is eligible to be considered for release by the Parole Board at the halfway point; for such sentences imposed before 1 February 2016, the prisoner was entitled to automatic release at the two-thirds point of the custodial term.
Extended Public Protection sentences (EPPs): (England and Wales only) which were the type of extended sentences that applied before the EDS was introduced in 2012; in the later version of the EPP (imposed between 2008 and 2012), release is automatic at the halfway point of the custodial term, and in the earlier version (pre-2008) release was via the Parole Board at that point.
Discretionary Conditional Release (DCR) sentences (England and Wales only) which applied under the Criminal Justice Act 1991 where release is via the Parole Board at the halfway point and automatic at the two-thirds point.
	In England and Wales, section 244 of the 2003 Act places a duty upon the Secretary of State to release those serving SDS on licence once they have served half of their sentence. This is known as automatic release. Automatic release historically applied to short term prisoners (those with sentences of less than 4 years) under section 33(2) of the Criminal Justice Act 1991.
	In Scotland, section 1 of the 1993 Act requires the Scottish Ministers to release a short-term prisoner automatically at the halfway point of their sentence. For long-term prisoners serving standard determinate sentences, they are eligible for discretionary release at the halfway point, and the duty to automatically release occurs 6 months before the end of the sentence if the prisoner has not been released earlier. Prior to 1 February 2016, such prisoners were also eligible for release at the halfway point, but automatically released at the two-thirds point.
	The Criminal Justice and Courts Act 2015 introduced the SOPC in England and Wales, which applies automatically to offenders convicted of a specific sexual or terrorist offence (as listed in Schedule 18A of the 2003 Act), in circumstances where the courts decide that neither the seriousness threshold for applying a life sentence, nor the dangerousness threshold for applying an EDS, have been met. Under section 244A of the 2003 Act, offenders serving these sentences must be released on licence at the end of their custodial term, but the Parole Board has the discretion to release from the halfway point if satisfied that the offender’s detention is no longer necessary for the protection of the public. As part of the SOPC, a further 12-month licence period is imposed to follow the custodial term, to manage the assessed risk the offender poses.
	The 2003 Act created new extended sentences (EPP) imposed under sections 227 and 228 of the 2003 Act (since replaced by the EDS). EPPs are subject to the release arrangements of section 247 of the 2003 Act. As enacted, release was subject to Parole Board discretion at the halfway point of the custodial term. In 2008, the Criminal Justice and Immigration Act 2008 altered that mechanism so that instead of referral to the Board at halfway point, release would be automatic at the halfway point.
	The EDS, introduced by the Legal Aid, Sentencing and Punishment of Offenders Act 2012, is an extended sentence imposed under sections 226A or 226B of the 2003 Act. Like the EPP, the Court imposes a custodial term commensurate with the seriousness of the offence for which the offender has been convicted and an extended preventative licence. The Court may impose an EDS where an offender has committed a specified violent, sexual or terrorist offence (as listed in Schedule 15 to the 2003 Act) and the courts find the offender to be ‘dangerous’. The Court sets a custodial term and an extended licence period. Under the EDS, an offender must be released at the end of their custodial term, but the Parole Board has the discretion to release from the two-thirds point if satisfied that the offender’s detention is no longer necessary for the protection of the public. As enacted, and prior to 13 April 2015, if the custodial term of an EDS was for a period of less than 10 years, and the offence was not listed in Schedule 15B to the 2003 Act, release was automatic at the two-thirds point – with no Parole Board consideration. This was amended by the Criminal Justice and Court Act 2015 which provided for Parole Board consideration of the release of all EDS sentenced offenders sentenced after that Act came into force. Fixed-term recall does not apply to the EDS sentence, so even when recalled EDS prisoners cannot be re-released automatically.
	In Scotland, extended sentences were introduced under the Crime and Disorder Act 1998 which inserted section 210A into the 1995 Act. Under section 210A the Court may impose an extended sentence if it is intending to pass a determinate sentence in relation to a sexual offence of any length, or a violent or terrorism offence of four years or more, and considers that the terms of a standard sentence would not be adequate for the purpose of protecting the public from serious harm from the offender. An extended sentence is made up of a custodial term and an extension period set by the Court (up to 10 years). Prisoners subject to an extended sentence are eligible for release by the Scottish Ministers on a recommendation from the Parole Board at the halfway point. Before commencement of the Prisoners (Control of Release) Scotland Act 2015 on 1 February 2016 prisoners were entitled to automatic release at the two-thirds point; since that time, automatic release is at the end of the custodial term.
	Schedule 20B of the 2003 Act contains release provisions which continue to apply to those serving sentences imposed under the Criminal Justice Act 1967 and the Criminal Justice Act 1991. Offenders sentenced under the 1967 and 1991 Acts are subject to discretionary conditional release. Offenders sentenced under these provisions before 3 December 2012 for offences committed before 4 April 2005, who received a sentence of 4 years or more for an offence listed in Schedule 15 to the 2003 Act, are subject to automatic release on licence at the two-thirds point, if not released by the Parole Board at the halfway point. The licence expires at the three-quarters point, meaning the offender is no longer subject to conditions and cannot be recalled to custody after that point. Schedule 20B also includes the release provisions for those who continue to serve the now repealed EPP sentences.