An information relating to an offence under this Part which is triable by a magistrates' court in England and Wales may be so tried on an information laid at any time within twelve months after the date on which evidence sufficient in the opinion of the Director of Public Prosecutions or the Secretary of State to justify the proceedings comes to his knowledge.

Proceedings in Scotland for an offence under this Part may be commenced at any time within twelve months after the date on which evidence sufficient in the Lord Advocate’s opinion to justify the proceedings came to his knowledge or, where such evidence was reported to him by the Secretary of State, within twelve months after the date on which it came to the knowledge of the latter.

For the purposes of this subsection proceedings shall be deemed to be commenced on the date on which a warrant to apprehend or to cite the accused is granted, if the warrant is executed without undue delay.

Subsection (1) does not authorise the trial of an information laid, and subsection (2) does not authorise the commencement of proceedings, more than three years after the commission of the offence.

For the purposes of this section a certificate of the Director of Public Prosecutions, the Lord Advocate or the Secretary of State as to the date on which such evidence as is referred to above came to his knowledge is conclusive evidence.

Nothing in this section affects proceedings within the time limits prescribed by section 127(1) of the [1980 c. 43.] Magistrates' Courts Act 1980 or section 331 of the [1975 c. 21.] Criminal Procedure (Scotland) Act 1975 (the usual time limits for criminal proceedings).