12Persons previously convicted may, on verdict, be imprisoned with or without hard labour
When any verdict shall pass or conviction be had against any person for any offence against the Customs Acts, and he shall have been adjudged to pay a penalty of one hundred pounds or upwards, the presiding justice may, if for a first offence, commit the offender to one of Her Majesty's prisons for not less than six nor more than nine months, and if for a subsequent offence may order that the offender shall, in lieu of payment of the penalty, be imprisoned, with or without hard labour, for a period not less than six nor more than twelve months.