SCHEDULE 1 – THE CRIMINAL CODE.
PART I. – INTRODUCTORY.
Division 3. – Application of the Criminal Law.
11. EFFECT OF CHANGES IN LAW.
(1) A person cannot be punished for doing or omitting to do an act unless–
(a) the act or omission constituted an offence under the law in force when it occurred ; and
(b) doing or omitting to do the act under the same circumstances would constitute an offence under the law in force at the time when he is charged with the offence.
(2) If the law in force when the act or omission occurred differs from that in force at the time of the conviction, the offender cannot be punished to any greater extent than was authorized by the former law, or to any greater extent than is authorized by the latter law.
Non-retroactivity
Nullum crimen sine lege
Nulla poena sine lege
EDIT.