s 227A Offences of threatening with a weapon in public or on school premises
(1) This section applies if— (a) a person aged 18 or over is convicted by a court of an offence under section 42 (criminal conduct); and (b) the corresponding offence under the law of England and Wales is an offence under section 1A of the Prevention of Crime Act 1953 or section 139AA of the Criminal Justice Act 1988 (threatening with article with blade or point or offensive weapon in public or on school premises). (1A) Where the offender is aged under 21 at the time of conviction, the court must impose a sentence of detention in a young offender institution for a term of at least 6 months unless the court is of the opinion that there are exceptional circumstances which— (a) relate to the offence or to the offender, and (b) justify not doing so. (2) Where the offender is aged 21 or over at the time of conviction, the court must impose a sentence of imprisonment for a term of at least 6 months unless the court is of the opinion that there are exceptional circumstances which— (a) relate to the offence or to the offender, and (b) justify not doing so. (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .