ABSTRACT
Chapter 3 begins the discussion of key general principles that drive criminal law. Of these general principles, perhaps the two most fundamental principles of all are actus reus and mens rea, both of which are discussed in this chapter. The chapter’s discussion begins by identifying actus reus (literally ‘guilty act’) as the external behaviour which criminal law defines as being a crime, and mens rea (literally ‘guilty mind’) as the blameworthy mind-set which is also required for some criminal offences alongside the actus reus. The discussion of actus reus notes that in practice, this concept includes a wider range of criminal behaviour than guilty acts. The discussion of mens rea explains how different types of mens rea – intention, recklessness and negligence – attach to different criminal offences, and notes that for a wide range of crimes, known as strict liability offences, no mens rea is needed at all. The second part of the chapter looks at how the concepts of actus reus and mens rea are used by the key players in the criminal justice process – police, the Crown Prosecution Service, the courts and victims of crime – before concluding by linking evidence back to criminal law and criminal justice roadmap models introduced in Chapter 1.
