- Actus Reus and Mens Rea
OVERVIEW OF TOPIC
The study of Criminal Law within your LLB or GDL can be one of the more interesting topics for students. It is important, however, to understand the key concepts in order to do well. This guide will go through, on a very basic level, the parts of homicide (Murder and Manslaughter) you will need to have knowledge of.
WHAT DOES HOMICIDE MEAN?
Homicide is really an umbrella term which encapsulates crimes resulting in death or GBH of the victim: Murder, both voluntary and involuntary as well as manslaughter.
ACTUS REUS AND MENS REA
Actus Reus: The act of the person
Mens Rea: The intent of the person
Fundamental to Criminal Law is the assertion that in order for a person to be found guilty of a crime there must not only be an act but an intention. Actus non facit reum, nisi mens sit rea in latin can be loosely translated to mean: An act cannot make a man guilty of a crime unless his mind was also guilty. (Lord Hailsham, Haughton v Smith 1975)
So, as we are considering homicide, a man would be guilty of murder if he had committed the act which resulted in death of the victim AND intended to kill or cause GBH to the victim.
In terms of the actus reus, an act is usually considered to be a positive act and will not include failure to act. However, as in many areas of law there are exceptions to this rule. Below are the five circumstances in which an a duty will be imposed to act:
- Where there is a special relationship. Parental relationships, doctor to patient and spouses will all fall under this category.Case examples – Downes , Gibbons and Proctor  Smith 
- Where there has been a voluntary assumption of responsibility for another person. Failure thereafter to care properly for the person will be considered an omission to act that is actionable.Case example – R v Stone and Dobinson 
Where the defendant has a duty to avert a danger they have created, such as a fire.
Case example – R V Miller 
- Where the duty is a contractual one, for example police officers to the public
Case example – R V Dytham
- Where there is a statutory duty ie one imposed by UK legislation. For example failure to report an accident as contrary to the Road Traffic Act 
If both the act and intention are present, a defendant may be able to provide a defence to lessen their liability in the situation. Defences for murder are:
- Provocation: The person must have been provoked to lose control and this loss of control must be reasonable.
- Diminished Responsibility: The defendant must prove they were suffering from an abnormality of the mind resulting from a condition that substantially impaired their mental responsibility at the time of the killing.
This article has aimed to provide a very basic understanding of the concepts of homicide in criminal law. This will allow those studying this subject as part of their degree to grasp the basics before moving on to further more in depth study.