Introduction to Exemptions from Criminal Liability in Ghana:
As a general rule, for a person to be found guilty of a crime, their actions must coincide with a criminal intent, or mens rea. This requirement is reflected in the maxim " actus non facit reum nisi mens sit rea," which means "an act does not render a man guilty of a crime unless his mind is equally guilty." It is also reflected in the statement of Lord Goddard CJ in Brend v. Wood:
It should first be observed that at common law there must always be mens rea to constitute a crime; if a person can show that he acted without mens rea that is a defence to a criminal prosecution. There are statutes and regulations in which Parliament has seen fit to create offences and make people responsible before criminal Courts although there is an absence of mens rea, but it is certainly not the Court’s duty to be acute to find that mens rea is not a constituent part of the crime. It is of the utmost importance for the protection of the liberty of the subject that a Court should always bear in mind that unless a statute, either clearly or by necessary implication, rules out mens rea as a constituent part of a crime, the Court should not find a man guilty of an offence against the criminal law unless he has a guilty mind.
A crime occurs when the actus reus and mens rea coincide in relation to the same event. However, some individuals are considered incapable of forming or possessing the necessary mens rea to commit a crime, and as such are exempt from criminal liability. An accused person may also be exempt from criminal liability if they have a defence that negates the actus reus or mens rea of the crime for which they are being prosecuted.
Summarily, a person is exempt from criminal liability if:
1. He is considered incapable of forming the necessary mens rea for a crime.
2. He has a defence that negates the mens rea or actus reus of the crime for which they are being prosecuted.
What it Means to be Incapable of Forming a Mens Rea:
Being "incapable of forming a mens rea" means that a person is unable to understand the nature and consequences of their actions, or is unable to form the necessary intent to commit a crime. This can occur for various reasons, such as infancy, insanity, inter alia.
Grounds for the Exception from Criminal Liability:
These grounds are explained in subsequent notes.