Legal background Sentencing and release
Sentences of imprisonment are generally served part in prison and part in the community. Under current legislation, determinate sentenced prisoners in England and Wales must be released in accordance with the provisions contained in Chapter 6 of Part 12 of the Criminal Justice Act 2003 ("the 2003 Act") which includes the legacy release provisions of the Criminal Justice Act 1991 which are restated in Schedule 20B of the 2003 Act, and indeterminate sentenced prisoners in accordance with Part 2 of the Crime (Sentencing) Act 1997. In Scotland, prisoners must be released in accordance with the terms of the Prisoners and Criminal Proceedings (Scotland) Act 1993 ("the 1993 Act"). In Northern Ireland, prisoners sentenced after April 2009 are released pursuant to the Criminal Justice (Northern Ireland) Order 2008 ("the 2008 Order").
	The following sentences (expanded upon below), which can currently be applied to those who have committed a terrorist or terror-related offence, are subject to changes by the Act:
Sentences for Offenders of Particular Concern (England and Wales) where a terrorist offender is eligible to be considered for release by the Parole Board at the two-thirds point of the custodial term, and will be subject to an extra 12-month licence period at the end of their custodial term.
Extended Determinate Sentences (England and Wales) where a terrorist offender is currently eligible to be considered for release by the Parole Board at the two-thirds point of the custodial term and will be subject to an extended licence period at the end of their custodial term.
Discretionary Life Sentences (England and Wales) where a terrorist offender is guilty of an offence which has a maximum punishment of life imprisonment, but where the judge has discretion to set the minimum term (tariff) to be spent in custody, after which they are eligible for release by the Parole Board. The subsequent licence period lasts for life.
Extended Sentences (Scotland) where a terrorist offender is currently eligible to be considered for release by the Parole Board at the two-thirds point of the custodial term and will be subject to an extended licence period on release.
Indeterminate Sentences (Scotland) where a terrorist offender is serving a sentence with no set end point, such as a life sentence. Release is discretionary by the Parole Board for Scotland after the minimum custodial term set by the Court is served. Once released, offenders are subject to licence conditions for life.
Determinate Custodial Sentences (Northern Ireland) where all offenders are currently released automatically on licence at the halfway point of the sentence.
Extended Custodial Sentences (Northern Ireland) where all offenders are currently eligible to be considered for release by the Parole Commissioners at the halfway point of the custodial term and will be subject to an extended licence period after the custodial term ends.
Indeterminate Custodial Sentences (Northern Ireland) where offenders are given an indeterminate sentence and become eligible to be considered for release by the Parole Commissioners after the minimum term or "tariff" has expired. These prisoners are subject to a licence for their lifetime unless revoked.
	Prisoners who are transferred on an unrestricted basis between the jurisdictions of the United Kingdom are, by virtue of Schedule 1 paragraph 15(2) of the Crime (Sentences) Act 1997, treated for "relevant purposes" (which include detention, release, supervision and recall) as if the person had been sentenced to an equivalent sentence in the receiving jurisdiction.