s 217 Mandatory life imprisonment
(1) This section applies if a person is convicted by the Court Martial of an offence under section 42 (criminal conduct) and the corresponding offence under the law of England and Wales is under that law— (a) murder; or (b) any other offence the sentence for which is fixed by law as imprisonment for life. (2) Where on conviction the offender is 21 or over, the court must sentence the offender to imprisonment for life. (3) Where on conviction the offender is aged under 21, the court must pass on the offender a sentence of custody for life under section 275 of the Sentencing Code. (4) Subsection (3) does not apply where the offender is liable to be detained under section 218 (detention at Her Majesty's pleasure for offender under 18).