9. The wording of Section 428 is, in our view, clear and unambiguous. The heading of the Section itself indicates that the period of detention undergone by the accused is to be set off against the sentence of imprisonment. The Section makes it clear that the period of sentence on conviction is to be reduced by the extent of detention already undergone by the convict during investigation, enquiry or trial of the same case. It is quite clear that the period to be set off relates only to pre conviction detention and not to imprisonment on conviction.
10. Let us test the proposition by a concrete example. A habitual offender may be convicted and sentenced to imprisonment at frequent intervals. If the period of pre-trial detention in various cases is counted for set-off in respect of a subsequent conviction where the period of detention is greater than the sentence in the subsequent case, the accused will not have to undergo imprisonment at all in connection with the latter case, which could not have been the intention of the legislature while introducing Section 428 in the Code in 1973.