Proceedings for an offence under section 23 may be brought within the period of 6 months from the date on which evidence sufficient in the opinion of the prosecutor to justify the proceedings came to the prosecutor's knowledge.

In a prosecution of an offence involving a continuous contravention, the entire period during which the contravention occurred may be included.

A certificate signed by or on behalf of the prosecutor which states the date on which evidence referred to in subsection (1) came to the prosecutor's knowledge is conclusive evidence of that fact; and such a certificate which purports to be so signed is to be treated as being so signed unless the contrary is proved.

For the purposes of this section, proceedings are deemed to be commenced on the date on which a warrant to apprehend or to cite the accused is granted provided that the warrant is executed without undue delay.