20.—(1) The Secretary of State may, if satisfied that exceptional circumstances exist which justify the release of a prisoner to whom this Article applies on compassionate grounds, at any time release the prisoner on licence under this Article.
(2) This Articles applies to—
(a)a fixed-term prisoner; and
(b)a prisoner serving an indeterminate custodial sentence.
(3) The Secretary of State shall, before releasing a prisoner serving—
(a)an indeterminate custodial sentence; or
(b)an extended custodial sentence,
consult the Parole Commissioners unless the circumstances are such as to render such consultation impracticable.
(4) In this Article “fixed-term prisoner” includes a person serving a determinate custodial sentence for an offence committed before the commencement of this Article.