Related Rule
Sierra Leone
Practice Relating to Rule 101. The Principle of Legality
Sierra Leone’s Constitution (1991) states:
23. Provision to secure protection of law.
(7) No person shall be held to be guilty of a criminal offence on account of any act or omission which did not, at the time it took place, constitute such an offence.
(8) No penalty shall be imposed for any criminal offence which is severer in degree or description than the maximum penalty which might have been imposed for that offence at the time when it was committed.
(10) Nothing contained in or done under the authority of any law shall be held to be inconsistent with or in contravention of any provisions of this section … to the extent that the law in question authorises the taking during a period of public emergency of measures that are reasonably justifiable for the purpose of dealing with the situation that exists before or during that period of public emergency.
29. Public emergency.
(2) The President may issue a Proclamation of a state of public emergency only when –
a. Sierra Leone is at war; [or]
b. Sierra Leone is in imminent danger of invasion or involvement in a state of war; or
c. there is actual breakdown of public order and public safety in the whole of Sierra Leone or any part thereof to such an extent as to require extraordinary measures to restore peace and security; or
d. there is a clear and present danger of an actual breakdown of public order and public safety in the whole of Sierra Leone or any part thereof requiring extraordinary measures to avert the same; or
e. there is an occurrence of imminent danger, or the occurrence of any disaster or natural calamity affecting the community or a section of the community in Sierra Leone; or
f. there is any other public danger which clearly constitutes a threat to the existence of Sierra Leone.
(5) During a period of public emergency, the President may make such regulations and take such measures as appear to him to be necessary or expedient for the purpose of maintaining and securing peace, order and good government in Sierra Leone or any part thereof. 
Sierra Leone, Constitution, 1991, Sections 23(7)–(8) and (10) and 29(2) and (5).