Rules and Principles (AQA A-Level Law): Revision Notes
Rules and principles
Criminal law is a substantive area of law assessed in Paper 1 of A-Level Law. It consists of common law rules and statutes that define prohibited conduct in society because it threatens or harms public safety.
Understanding the fundamental rules and principles of criminal law is essential before examining specific offences. These principles form the foundation for all criminal liability and will be referenced throughout your study of specific offences.
Defining crime
Crime was defined by Lord Atkin in Proprietary Articles Trade Association v Attorney-General for Canada (1931) as an act prohibited with penal consequences.
For conduct to be classified as a crime, two essential elements must be present:
The Two Essential Elements of Crime:
1. The act must be prohibited The conduct must be forbidden by the state. The state has declared this behaviour unacceptable and unlawful.
2. The act must attract penal consequences There must be punishment imposed by the state. A maximum or mandatory sentence must be available if a person is convicted.
Without both elements, conduct cannot be considered a criminal offence. All crimes, regardless of type, share these two characteristics.
Sources of criminal law
Criminal offences are created through two main sources:
Statute law Most crimes are created by Parliament through Acts of Parliament. Parliament responds to changing social circumstances by passing legislation that criminalises new forms of harmful behaviour.
Examples include:
- Fraud Act 2006 – created statutory fraud offences
- Criminal Justice and Courts Act 2015 – outlawed 'revenge porn'
Common law Some crimes have been developed over time by judges using the doctrine of precedent. These offences have never been set down by Parliament but evolved through case law.
The most significant example is murder, which has never been defined by statute but developed entirely through judicial decisions over centuries.
Although rare today, judges can still create new crimes. In R v R (1991), the courts established that a husband could be guilty of raping his wife, effectively creating the offence of marital rape through common law.
General elements of criminal liability
The fundamental principle of English criminal law was stated by Edward Coke in the seventeenth century:
"Actus non facit reum nisi mens sit rea"
This Latin maxim means: an act is not guilty unless the mind is also guilty.
This principle establishes that for most criminal offences, two distinct elements must be present.
Actus reus (AR)
The actus reus is the guilty act or external element of a crime. It refers to the prohibited conduct, circumstance, or consequence that the law forbids.
Mens rea (MR)
The mens rea is the guilty mind or mental element of a crime. It refers to the defendant's state of mind at the time of the prohibited act, such as intention or recklessness.
Coincidence of actus reus and mens rea
Both elements must occur at the same time for a crime to be committed. The defendant must have the required mental state at the moment they perform the prohibited act.
If the defendant commits the actus reus without the appropriate mens rea, they cannot be guilty of that offence. For example, if someone kills another person but does not intend to kill them, they cannot be guilty of murder (though they may be guilty of a different offence such as manslaughter).
Worked Example: Criminal Attempts
Section 1(1) of the Criminal Attempts Act 1981 defines the offence of attempt. A person is guilty of attempting to commit an offence if they perform an act which is more than merely preparatory to the commission of the offence, with the intention of committing that offence.
This offence demonstrates the AR/MR structure:
- Actus reus: An act more than merely preparatory to committing the offence
- Mens rea: Intention to commit the offence (recklessness is insufficient for attempt)
Note that attempt requires intention even if the substantive offence can be committed recklessly. This makes the mens rea for attempt more restrictive than some completed offences.
Defending crime – removing liability
Even if the defendant has committed both the actus reus and mens rea of an offence, they may still avoid criminal liability through a general defence. If successfully raised, a general defence leads to a complete acquittal (not guilty verdict).
For A-Level, you must study the following general defences:
- Self-defence/prevention of crime
- Duress by threats
- Duress of circumstances
- Insanity
- Automatism
- Intoxication
Categories of defences
General defences can be classified into two categories:
1. Capacity defences These defences argue that the defendant could not form the mens rea of the offence. The defendant's capacity to form criminal intent was impaired or absent.
Examples include:
- Insanity
- Automatism
- Intoxication (in limited circumstances)
2. Necessity defences These defences acknowledge that the defendant did form the mens rea but had an 'excuse' or justification for their actions. The defendant chose to act but had compelling reasons.
Examples include:
- Self-defence/prevention of crime
- Duress by threats
- Duress of circumstances
Understanding whether a defence is based on capacity or necessity helps determine how it operates and what the defendant must prove. This distinction is crucial when applying defences to problem scenarios.
Proving criminal liability
Criminal proceedings operate under specific rules regarding who must prove what, and to what standard.
Burden of proof
The burden of proof rests on the prosecution. This means:
A defendant is innocent until proven guilty. The prosecution bears responsibility for providing evidence in court that the defendant committed both the actus reus and mens rea of the offence charged.
The defendant does not have to prove their innocence. They can remain silent and require the prosecution to prove the case against them.
Exception: In certain defences (particularly insanity), the defendant may bear the burden of proving the defence on the balance of probabilities. This shifts the burden but only in limited circumstances.
Standard of proof
The prosecution must prove the defendant's guilt beyond all reasonable doubt (also expressed as "so that you are sure").
This means the jury or magistrates should only convict if they are satisfied on the evidence that they are certain of the defendant's guilt. Any reasonable doubt should result in acquittal.
This is a higher standard than in civil law, where the standard is 'balance of probabilities' (more likely than not). The higher criminal standard reflects that a person's liberty is at stake in criminal proceedings.
Worked Example: Applying the Standard of Proof
If the jury thinks the defendant is probably guilty but has some reasonable doubt, they must acquit. Anything less than being sure of guilt is insufficient for conviction.
This high standard protects defendants but may also mean that some who committed the act are acquitted due to insufficient evidence.
Evaluation: Burden and standard of proof
The interaction between general defences and burden/standard of proof raises important questions:
Arguments for current approach:
- Protects defendants by requiring prosecution to prove all elements
- High standard reflects seriousness of criminal conviction
- Presumption of innocence is a fundamental right
Arguments for reform:
- Placing burden on defendant for some defences (e.g. insanity) may be unfair
- Difficult for prosecution to disprove defences like duress
- May lead to acquittals where defendant clearly committed act
The balance between protecting defendants and ensuring justice for victims remains contentious. This is an ongoing debate in criminal law reform and provides excellent material for evaluation in essays and problem questions.
Key Points to Remember:
Essential Concepts:
- Crime has two elements: the act must be prohibited and attract penal consequences
- Most crimes require both actus reus (guilty act) and mens rea (guilty mind) occurring at the same time
- Crimes are created by statute (Parliament) or common law (judges)
- General defences are either capacity defences (couldn't form mens rea) or necessity defences (had excuse for forming mens rea)
- The burden of proof is on the prosecution to prove guilt beyond all reasonable doubt
Key Terminology:
- Actus reus: the guilty act or external element of a crime
- Mens rea: the guilty mind or mental element of a crime
- Burden of proof: prosecution's responsibility to prove guilt
- Standard of proof: beyond all reasonable doubt/so that you are sure
- Capacity defences: defences where defendant couldn't form mens rea
- Necessity defences: defences where defendant had excuse for actions
Critical Principles for Exams:
- Latin maxim: actus non facit reum nisi mens sit rea – an act is not guilty unless the mind is also guilty
- Lord Atkin's definition in Proprietary Articles Trade Association v Attorney-General for Canada (1931)
- Higher standard of proof in criminal law than civil law reflects that liberty is at stake