2.1 Elements of a Crime


2026 📋 Syllabus Objectives

By the end of these notes, you should be able to:

  • Understand what fault means in criminal law and why it matters
  • Explain what actus reus is, including acts, omissions, and states of affairs
  • Understand when a failure to act (omission) can lead to criminal liability
  • Explain causation — the "but for" test, the thin-skull rule, and intervening acts
  • Explain mens rea, including intention (direct and oblique) and recklessness
  • Understand the principle of transferred malice
  • Explain the contemporaneity rule — why both elements must happen at the same time

1. The Basics: What Is Fault in Criminal Law?

Criminal law is about holding people responsible when they do something wrong — whether that wrong is against another person, against society, or against the state.

In law, fault means blameworthiness — the idea that a person deserves to be blamed and punished for their actions.

To prove that someone is at fault and therefore criminally liable (meaning responsible in the eyes of the law), two separate elements must both be proved:

ElementLatin NamePlain English Meaning
Physical elementActus reusWhat the defendant did (or failed to do)
Mental elementMens reaWhat the defendant was thinking at the time

💡 Think of it this way: actus reus = the guilty act; mens rea = the guilty mind.

Both elements must be proved to the standard of beyond reasonable doubt — meaning the judge or jury must be sure the defendant is guilty before they can be convicted.


Types of Crimes: Conduct Crimes vs. Result Crimes

Crimes can be split into two categories:

  • A conduct crime is one where simply doing the act is the offence — regardless of what happens afterwards. For example, theft is a conduct crime. The act of taking someone else's property is itself the crime.

  • A result crime is one where a specific outcome must happen for it to count as a crime. For example, criminal damage requires that property is actually damaged. The result must occur.

This matters because in result crimes, the prosecution must also prove that the defendant caused that result — which is covered in the section on causation below.

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