(1) Notwithstanding any provision in any British statute or Act of the Oireachtas limiting the period within which summary proceedings may be commenced, proceedings for an offence under the Act of 1909 or for an offence under this Act shall not be commenced more than six years after the commission of the offence but, subject to that limitation, may be commenced at any time within six months from the date on which evidence, sufficient in the opinion of the Minister to justify a prosecution for the offence, comes to his knowledge, or within one year after the commission of the offence, whichever period is the longer.
(2) For the purposes of this section, a certificate by the Minister, sealed with his seal of office, stating the date on which evidence, sufficient in the opinion of the Minister to justify a prosecution for a specified offence, came to his knowledge shall be conclusive evidence of such date.