Core principles of criminal liability - Specified criminal o...

Learning Outcomes

This article outlines the core principles of criminal liability as applied to specified criminal offences, including:

• Distinguishing conduct, circumstance, and result elements in actus reus across assault/battery, ABH (s 47), GBH (s 20), GBH with intent (s 18), theft, robbery, burglary, aggravated burglary, criminal damage, arson, and fraud
• Identifying the appropriate mens rea (intention, oblique intention, recklessness, knowledge) for each offence and when “maliciously” denotes intention or recklessness as to some harm
• Analysing when a failure to act becomes criminal given a recognised duty to act, and which offences can be committed by omission
• Assessing factual and legal causation, including intervening acts and application of the thin skull rule
• Applying contemporaneity (coincidence) principles—continuing acts and single transaction—to ensure actus reus and mens rea align
• Evaluating when statutory offences are strict liability and how the presumption of mens rea may be displaced
• Mapping these principles onto common SQE2 fact patterns to structure analysis and predict likely outcomes

SQE2 Syllabus

For SQE2, you are required to understand the core principles of criminal liability as they apply to specified criminal offences, including actus reus, mens rea, omissions, causation, strict liability, and contemporaneity, with a focus on the following syllabus points:

• differentiating and defining actus reus and mens rea
• explaining and applying the law on omissions and duties to act
• analysing the importance of causation—including when liability is interrupted by intervening acts
• describing strict liability and its boundaries
• applying contemporaneity (coincidence) principles to ensure actus reus and mens rea coexist in time
• recognising how these principles map onto the specified offences commonly assessed.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Define actus reus and mens rea. How do they interact in establishing liability for a criminal offence?
2. Explain how an omission can result in criminal liability. What are the key established duties to act?
3. What test is used by the courts to determine legal causation, and how can the chain of causation be broken?
4. What is strict liability, and why might Parliament create a strict liability offence?

Introduction

Understanding criminal liability for specified offences begins with comprehending the essential elements—actus reus and mens rea. These elements set the structure for applying criminal law to practical scenarios. In addition, omissions, causation, and strict liability can complicate how liability is imposed or broken. For SQE2, candidates must have a working knowledge of how these principles combine in real cases.

Elements of Criminal Liability

The prosecution must prove both a conduct element (actus reus) and a fault element (mens rea) for most offences, unless dealing with strict liability offences. In the specified offences:

• For assault and battery, the actus reus is causing apprehension of immediate unlawful personal violence (assault) or the application of unlawful force (battery). The mens rea is intention or recklessness for each base offence.
• For assault occasioning actual bodily harm (OAPA 1861, s 47), the actus reus is a base assault or battery which causes ABH. The mens rea is only that for the base assault or battery; there is no additional mens rea as to harm.
• For malicious wounding/inflicting grievous bodily harm (OAPA 1861, s 20), the actus reus is causing a wound (breaks both layers of the skin) or GBH (really serious harm). “Maliciously” means intention or recklessness as to some harm.
• For wounding/causing grievous bodily harm with intent (OAPA 1861, s 18), the actus reus is the same as s 20; the mens rea is a specific intent to cause GBH, or intent to resist lawful apprehension plus “maliciousness” (intention or recklessness as to some harm).
• For theft (TA 1968, s 1), the actus reus comprises appropriation of property belonging to another; the mens rea comprises dishonesty and intention to permanently deprive.
• For robbery (TA 1968, s 8), there must be a completed theft and force or the fear of force is used immediately before or at the time and in order to steal.
• For burglary (TA 1968, s 9), entry as a trespasser into a building or part with ulterior intent (s 9(1)(a)), or commission/attempt of theft or GBH after trespassory entry (s 9(1)(b)).
• For aggravated burglary (TA 1968, s 10), the burglary is aggravated by having a firearm, imitation firearm, weapon or explosive with you at the time.
• For criminal damage (CDA 1971, s 1(1)), the actus reus is destroying or damaging property belonging to another; the mens rea is intention or recklessness as to damage and knowledge/belief that property belongs to another. Aggravated criminal damage (s 1(2)) adds the ulterior mens rea of intending or being reckless as to endangering life by the damage.
• For arson (CDA 1971, s 1(3)), the same elements are present but damage is caused by fire.
• For fraud (Fraud Act 2006), the actus reus depends on the mode—false representation (s 2), failing to disclose information (s 3), or abuse of position (s 4); the mens rea is dishonesty and intention to make a gain or cause loss or risk of loss.

Key Term: actus reus
The actus reus is the external element of a criminal offence. It includes the defendant’s conduct, the circumstances, or a result required by the offence.

Key Term: mens rea
The mens rea is the internal, fault-based element of a criminal offence. It encompasses the defendant’s intention, knowledge, recklessness, or (rarely) negligence.

Actus reus can be categorised into conduct, circumstance and result elements. Ensuring voluntariness is essential: an involuntary movement (e.g., reflex action, genuine automatism) will not satisfy actus reus. Mens rea varies across offences: murder and s 18 GBH require specific intent; many offences accept recklessness (e.g., s 20, criminal damage). For recklessness, courts ask whether the defendant actually foresaw a risk and, given the circumstances known to them, it was unreasonable to take that risk.

Criminal liability also requires contemporaneity: the actus reus and mens rea must coexist in time. Courts use the “continuing act” principle (e.g., ongoing application of force) and the “single transaction” principle where a sequence of acts forms one criminal episode, to ensure coincidence is properly assessed.

Worked Example 1.1

A shoplifter picks up a sandwich intending to steal it, but then puts it back before leaving the shop. Is she guilty of theft?

Answer:
No. She formed the mens rea (intention to permanently deprive), but did not complete the actus reus (no appropriation—she did not leave with the property belonging to another). Both elements must be present at the same time.

A practical point: appropriation is broadly defined as “any assumption of the rights of an owner”. In many scenarios, appropriation can occur before an item is removed from a premises, but liability still requires dishonesty and the intention to permanently deprive to coincide with appropriation.

Worked Example 1.2

Fagan drives onto a police officer’s foot accidentally. On realising, he refuses to move the car for several minutes. Is the coincidence of actus reus and mens rea satisfied?

Answer:
Yes. The application of unlawful force (the car resting on the foot) is treated as a continuing act. When Fagan becomes aware and decides not to remove the car, his mens rea coincides with the ongoing actus reus.

Worked Example 1.3

Dee throws a stone at Pat intending to injure Pat, but misses and breaks a window. Is Dee liable for criminal damage via transferred malice?

Answer:
No. Transferred malice operates only where the offence type matches. Malice directed at injuring a person does not transfer to an offence against property.

Omissions and Duties to Act

Generally, criminal liability arises through positive acts, but failing to act can also establish liability where a duty exists.

Key Term: omission
An omission is a failure to act where the law imposes a duty to act, making the person potentially liable for resulting harm.

Key Term: duty to act
A duty to act is a legal obligation, which may arise from relationships (parent–child), employment, assumption of care, creation of a dangerous situation, or statute.

Recognised sources of duty include:

• special relationships (e.g., parent–child, Gibbons & Proctor)
• contract or employment (e.g., gatekeeper failing to lower crossing, Pittwood; professionals such as lifeguards and nurses in the course of duty)
• voluntary assumption of care (e.g., Stone & Dobinson)
• creation or contribution to a dangerous situation (e.g., starting a fire and failing to take reasonable steps to put it out, Miller)
• statutory duties (e.g., specific safety or reporting duties).

The scope and content of the duty depends on context. Once a duty is established, liability hinges on whether failing to act contributed to the prohibited result and whether the result offence can be committed by omission (e.g., ABH and GBH can be committed by omission; unlawful act manslaughter cannot—its “base offence” must be a positive act).

Worked Example 1.4

Paula, a lifeguard, sees a child drowning but does nothing. Is she criminally liable if the child dies?

Answer:
Yes, Paula may be liable for manslaughter by omission because her employment gives her a duty to act. Failing to rescue the child when her duty required it results in liability if the omission causes death.

Worked Example 1.5

Chris falls asleep with a lit cigarette, starting a smouldering fire in his flat. He wakes, notices the smoke, and leaves without attempting to extinguish it or summon help. The fire spreads, injuring a neighbour. Can Chris be liable?

Answer:
Yes. By creating a dangerous situation, Chris had a duty to take reasonable steps to avert harm. His omission can ground liability for offences capable of being committed by omission (e.g., criminal damage or, if death results and elements are proved, gross negligence manslaughter).

Revision Tip

Duties to act are limited—memorise the main categories for the exam: relationship, employment, assumption of care, creation of danger, or statute.

Causation and Intervening Acts

For result crimes, such as murder or actual bodily harm, causation links the defendant’s actions (or omissions) with the prohibited consequence.

Key Term: causation
Causation means proving that the defendant’s conduct was a substantial, blameworthy, and operative cause of the prohibited outcome.

Key Term: intervening act (novus actus interveniens)
An intervening act is a new, independent event that significantly breaks the chain of causation and may relieve the defendant of liability for the ultimate result.

Causation involves two stages:

• Factual causation: the “but for” test—would the result have occurred but for the defendant’s conduct?
• Legal causation: was the defendant’s conduct a substantial and operative cause of the result?

Key points:

• The “thin skull” rule: take the victim as found (unknown vulnerabilities do not break causation).
• Medical treatment: negligence rarely breaks the chain; only “palpably wrong” treatment that renders the original wound insignificant will do so.
• Victim’s acts: reasonable, foreseeable reactions to the defendant’s conduct (e.g., escaping perceived assault) do not break the chain; wholly unreasonable acts may.
• Third-party acts: a free, deliberate, and informed act may break causation if it is sufficiently independent and potent.

Worked Example 1.6

Craig stabs Sam lightly. In hospital, a doctor acts grossly negligently, causing Sam’s death. Is Craig liable for homicide?

Answer:
Possibly not. While Craig’s act was the factual cause, the grossly negligent medical care is an intervening act (novus actus interveniens) that may break the legal chain of causation if the original injury had substantially healed and the negligence alone caused death.

The same careful analysis applies to endangerment-of-life in aggravated criminal damage: life must be endangered by the damage itself, not solely by the act used to cause the damage.

Exam Warning

Where an intervening act is claimed, analyse carefully if the defendant’s actions are still a significant, operative cause, or if later events are so independent and potent that liability is broken.

Strict Liability

Some statutory offences do not require proof of mens rea for some or all elements—these are strict liability offences. They are usually regulatory and punishable by fine.

Key Term: strict liability
Strict liability offences do not require proof of fault (mens rea) for at least part of the actus reus; liability attaches once the prohibited act or omission is proved.

Courts start from a presumption that Parliament intends a mental element unless the statute clearly or by necessary implication excludes it. This presumption is strong for “truly criminal” offences (e.g., those carrying stigma or serious sentences) and weaker for public welfare/regulatory offences (e.g., food safety, environmental protection, road traffic).

Indicators and limits:

• The presumption of mens rea can be displaced where public safety is critical and Parliament’s purpose would be undermined by requiring fault.
• Strict liability still requires a voluntary act; it does not criminalise pure accidents.
• Many road traffic offences (e.g., speeding) are strict liability; by contrast, theft and fraud clearly require fault.

Worked Example 1.7

A market trader sells food unfit for human consumption, honestly believing it is safe. Is she criminally liable?

Answer:
Yes, if the relevant statute creates a strict liability offence (common in public health law), her lack of fault is irrelevant—liability arises once the court finds she sold unsafe food.

Strict liability does not broaden criminal liability without safeguards. Where a statute is silent, courts interpret it in line with established principles: if mens rea is not excluded by clear words or necessary implication, a mental element will be read in; if excluded, liability follows on proof of the actus reus alone.

Key Point Checklist

This article has covered the following key knowledge points:

• The elements of criminal liability are actus reus (prohibited conduct/circumstance/result) and mens rea (fault element).
• Both actus reus and mens rea must be proved for most offences; they must coincide in time. Continuing act and single transaction principles ensure coincidence is properly assessed.
• Omissions can result in liability where there is a legal duty to act; usual sources: special relationship, contract, assumption of care, danger creation, or statute.
• For result crimes, causation must be established—both factual (“but for” test) and legal (“substantial and operative” cause). The thin skull rule applies.
• The chain of causation can be broken by intervening acts (novus actus interveniens) if sufficiently independent and potent; medical negligence must be “palpably wrong” to break the chain.
• Strict liability offences require no proof of mens rea for at least some elements—commonly regulatory and aimed at protecting the public; voluntary conduct remains necessary.

Key Terms and Concepts

• actus reus
• mens rea
• omission
• duty to act
• causation
• intervening act (novus actus interveniens)
• strict liability