(2) In every case of an offence— fine, etc. (a) punishable with imprisonment as well as fine, in which the offender is
sentenced to a fine, whether with or without imprisonment;
(b) punishable with imprisonment or fine, or with fine only, in which the offender is sentenced to a fine,
it shall be competent to the Court which sentences such offender to direct by the sentence that, in default of payment of the fine, the offender shall suffer imprisonment for a certain term, in which imprisonment shall be in excess of any other imprisonment to which he may have been sentenced or to which he may be liable under a commutation of a sentence.