Actus Reus Lecture

Elements of an Offence

In deciding whether an individual is liable for an offence, three questions arise.

• The external elements of the offence must be present (actus reus)
• The defendant must have any state of mind required by the offence (mens rea)
• There must be no valid defence

In later chapters it will be seen that some offences dispense with proof of a state of mind for one or more elements (strict liability offence, for example), but in every case, the actus reus must be proved before a conviction can occur.

Although in most cases a defendant is required to do something in order to satisfy the actus reus, situations where this is not the case will be discussed below. Additionally, in certain circumstances, the actus reus requires an additional factor to exist or some specific consequence to follow in order for the actus reus to be established. Under section 18 of the Offences Against the Person Act 1861, for example, the defendant’s actions must wound or cause grievous bodily harm to the victim. The act of assaulting the victim will not be sufficient to satisfy the actus reus without this particular consequence. The distinction is described as being a conduct crime or a result crime.

A further example can be found under section 1(1) of the Criminal Damage Act 1971 which provides:

A person who without lawful excuse destroys or damages any property belonging to another intending to destroy or damage any such property or being reckless as to whether any such property would be destroyed or damaged shall be guilty of an offence.

The actus reus of the offence includes conduct causing damage to or destruction of property which belongs to another. Under section 10(2), property can belong to another even if the defendant also owns it. For example, a co-owner has a proprietary interest in it. In other words, all three elements/types of actus reus are included.

• Conduct - an act, or an omission where there is a duty to act, which causes the damage;
• Circumstance - the property belongs to somebody other than the defendant;
• Result - the property is damaged or destroyed.

If this offence is contrasted with the offence of rape, section 1 of the Sexual Offences Act 2003 provides that:

1. A person (A) commits an offence if -
   1. he intentionally penetrates the vagina, anus or mouth of another person (B) with his penis,
   2. B does not consent to the penetration, and
   3. A does not reasonably believe that B consents.

The actus reus is penile penetration of the other person’s vagina, anus or mouth without that person’s consent. The intention to penetrate and the absence of a reasonable belief in consent are separate requirements. No particular injury or other result is necessary.

Liability for Omissions

In most cases, a defendant will be required to act in order to satisfy the actus reus of an offence; the defendant must do something. There is no general requirement under English and Welsh law for a person to act. If, for example, a person sees another drowning and can easily save them by throwing into the water a nearby buoyancy aid, the person decides not to throw in the aid and the drowning person dies, the person who could have affected the rescue will not be guilty of an offence. This assumes the potential rescuer is a bystander who owes no duty to the drowning person.

There are however, several circumstances where a duty to act is imposed and where omission can satisfy the actus reus of an offence.

Statutory Duty

There are numerous statutory provisions that require an individual to act in a particular manner and which, if the individual does not act in that manner, cause the individual to be criminally liable. Under section 7(6) of the Road Traffic Act 1988, for example, it is an offence without reasonable excuse to fail to provide a specimen lawfully required for analysis. Section 170 requires a driver to stop after an accident on a road or other public place involving injury to another person or damage of a kind specified in the section. An officer of a company that fails to keep adequate accounting records may also commit an offence under sections 386 and 387 of the Companies Act 2006.

Duty Arising from a Special Relationship

Care or Control of Children

Section 1 of the Children and Young Persons Act 1933 makes it an offence for anyone aged 16 or over, including a parent, who has responsibility for a child under the age of 16 years to wilfully neglect the child in a manner likely to cause unnecessary suffering or injury to health. This can include a failure to provide adequate food, clothing, lodging or medical aid. Whilst this is a statutory provision and could easily fall within the previous section, it has links to liability that falls outside the express wording of the Act. Under this provision, a parent who deliberately fails to take an available step to save their child may be liable in the example set out above. Therefore, the term neglect relates to the care of the child in a general sense.

Assumption of Care for Another

Section 1 protects children under 16. At common law a parent does not owe a duty to care for an independent 18-year-old simply by virtue of parenthood (R v Shepherd (1862) 9 Cox CC 123). However, two important judgments highlight the approach that is taken in respect of where care is assumed for an adult.

Contractual Duties

A person may be found criminally liable if they fail to comply with a contractual duty they have to another. The most commonly cited example of this approach is found in R v Pittwood (1902) 19 TLR 37. In this case, the defendant was employed to operate the gates at a level crossing. He failed to close the gates when a train was approaching and a cart was struck by the train killing one of the carters. Pittwood was convicted of manslaughter. Although the position is described as being based on Pittwood’s breach of contractual duty, the victim was not a party to the contract and therefore, it was a breach of Pittwood’s duty to the crossing users that founded his liability. The contractual element arising out of the fact that this duty arose from his contractual obligation to manage the crossing. The contract may therefore give rise to a duty to people outside it. A hospital doctor, for example, owes a duty of care to the patients they treat.

Duty Arising out of a Danger of One’s Own Making

Where a person creates a dangerous situation, they may be placed under an obligation to take reasonable steps to remove the danger and therefore, may be criminally liable if they do not do so. In R v Miller [1983] 2 AC 161, the defendant was squatting in a building and fell asleep on a mattress whilst smoking a cigarette. He woke up to find that the mattress was smouldering, but rather than attempting to put the fire out, he simply moved to another room thereby allowing the fire to spread. The defendant’s conviction for arson was not based on the fact that he deliberately started the fire, but on his failure, once he became aware of the fire, to take steps within his power to prevent further damage. He was reckless as to that damage.

In R v Evans [2009] EWCA Crim 650, the defendant supplied her half-sister with heroin and failed to summon help after she overdosed. A person who creates or contributes to a situation which they know, or ought reasonably to know, has become life-threatening will normally have a duty to take reasonable steps to save the other person. For gross negligence manslaughter the prosecution must prove that the breach caused or contributed more than minimally to death, that it carried a serious and obvious risk of death reasonably foreseeable at the time, and that the negligence was gross. A lost chance of survival alone is insufficient (R v Broughton [2020] EWCA Crim 1093).

Medical Treatment

In ordinary circumstances, as was set out above, doctors are required to act in order to provide their patients with proper medical treatment. Unless a statutory power to treat without consent applies, an adult with capacity can refuse treatment even if that refusal will result in death. Where an adult lacks capacity, a valid and applicable advance decision to refuse that treatment must be respected. Otherwise, the decision under the Mental Capacity Act 2005 must be made in the patient’s best interests, taking their wishes and feelings into account.

In Airedale National Health Service Trust v Bland [1993] AC 789, doctors sought the court’s permission to withdraw clinically assisted nutrition and hydration from a patient who was in a persistent vegetative state, but who was able to breathe unaided. The House of Lords held that discontinuing treatment which was no longer in the patient’s best interests was a lawful omission. It distinguished administering a drug to bring about death from giving appropriate pain relief despite a foreseeable risk of shortening life. In An NHS Trust v Y [2018] UKSC 46, the Supreme Court held that a court order is not invariably required to withdraw clinically assisted nutrition and hydration if the Mental Capacity Act and professional guidance are followed and those concerned agree. A ruling should be sought if the decision is finely balanced or there is disagreement.

Offences Requiring a Positive Act

Offences that specifically require a positive act cannot be committed by omission alone. Burglary requires entry as a trespasser. A battery may involve a continuing act, as where the defendant knowingly left his car on a police officer’s foot after initially driving onto it by accident (Fagan v Metropolitan Police Commissioner [1969] 1 QB 439). In DPP v Santa-Bermudez [2003] EWHC 2908 (Admin), a false assurance about a needle in a pocket exposed a searching officer to injury and there was a case to answer in assault occasioning actual bodily harm. For theft, appropriation can include later keeping as owner property originally acquired innocently (Theft Act 1968, section 3(1)). For rape, penetration is a continuing act from entry to withdrawal (Sexual Offences Act 2003, section 79(2)). If consent is withdrawn, intentionally continuing penetration without a reasonable belief in consent can constitute rape.

Summary on Liability for Omission

• There is no general liability for omission.
• Depending on the offence, a duty to act may arise if:
  • A statutory duty to act exists;
  • The relationship gives rise to a duty, as between a parent and a dependent child;
  • The defendant has adopted a caring role towards the victim;
  • The defendant’s contract or public office imposes a duty. In R v Dytham [1979] QB 722, an on-duty police officer who wilfully failed to intervene in a fatal attack was convicted of misconduct in public office;
  • The defendant has created or contributed to a dangerous situation.

Voluntary Conduct

Where the offence requires an act, it must generally be voluntary. Some offences are defined by a state of affairs, such as being in charge of a motor vehicle on a road or other public place while over the alcohol limit (Road Traffic Act 1988, section 5(1)(b), subject to the defence in section 5(2)). This does not mean that the defendant must have deliberately done a particular thing. In other words, the actus reus of battery will be satisfied if the defendant unlawfully punches a victim where the only though process is the decision to knock the victim out - it is not necessary for the defendant to actively think ‘I will clench my fist, raise my arm’ etc. However, if a defendant is knocked off balance and falls against another person without any control over the movement, there will be no actus reus. This is because the defendant’s actions were out of their control. The distinction is one between an act that the defendant does and one that happens to the defendant. Only the former is a voluntary act.

Automatism

Automatism requires a total loss of voluntary control. Impaired control or inability to remember what happened is insufficient. The full definition will be considered in a subsequent chapter in relation to the similar and connected defence of insanity. It is important to note at this stage however, that sane automatism, usually due to an external factor, leads to an acquittal if the prosecution cannot disprove it once properly raised. Prior fault may defeat the defence. Where the cause is a disease of the mind, the rules on insanity apply.

Causation

In order for a defendant to be found liable for a result crime, the prosecution must prove that their conduct caused the prohibited result. In the example above, a person was considered to satisfy the actus reus of battery if they unlawfully punch another person. However, what would be the situation if the victim jumped aside to avoid the punch and fell down a steep slope hitting their head and subsequently dying from their injuries? Would the defendant be liable for the death? In other words, could the defendant be considered to have caused the victim’s death? Causation addresses the link between the defendant’s conduct and the prohibited result.

Causation falls into two categories: factual causation and legal causation - both must be satisfied where the offence requires a result.

Factual Causation

Factual causation is often alternatively known as ‘but for’ causation. The question that is asked is whether ‘but for’ the defendant’s actions, the harm to the victim would have occurred when it did. Causing death includes accelerating it. In R v White [1910] 2 KB 124, the defendant laced his mother’s bedtime drink with potassium cyanide. When the mother was found dead the following morning, the defendant was charged with her murder. It subsequently came to light however, that the medical evidence pointed to heart failure and did not establish that the poison caused her death. The result was that the defendant could not be considered to have caused the death and was only guilty of attempted murder.

Although in White, factual causation was absent, it can be seen that in many circumstances it would easily be found. The victim in the example would still be alive if the punch had not been thrown. Indeed, it is possible that a chain of events could flow from a single act of a defendant. Suppose in the punch example, the victim was collected by ambulance and taken to hospital, but on the way to the hospital, the ambulance crashed into a school bus killing several of the children on the bus. But for the defendant’s punch, the children would still be alive. Could it be considered that the defendant caused the death of the children?

Multiple Causes

A defendant may be guilty of causing something to happen if his conduct was not the only cause of it, even if his conduct alone was not sufficient to cause the harm to occur (R v Warburton [2006] EWCA Crim 627). There is no percentage test. The contribution must be more than minimal (R v Hennigan [1971] 3 All ER 133 and R v Notman [1994] Crim LR 518). Two people can each be a legal cause of the same harm.

Legal Causation

It is not difficult to see that factual causation is extremely broad and that a defendant can be found to be the factual cause of a victim’s harm even if the harm is far removed from the defendant’s actions. Legal causation has the effect of limiting this potentially broad liability.

The following points help identify a legal cause:

• The cause must be substantial to the extent that it is more than slight or trifling (R v Kimsey ([1996] Crim LR 35));
• It is the conduct prohibited by the offence that must contribute to the result. In R v Dalloway (1847) 2 Cox CC 273 the question was whether holding the reins would have prevented the child’s death (see also R v Hughes [2013] UKSC 56);
• The defendant’s actions must remain an operating cause when the harm occurs (R v Pagett (1983) 76 Cr App R 279).

These elements may not be present and the defendant may avoid liability even if found to have factually caused the victim’s harm in two circumstances. These can be categorised as:

• some act of another person that intervenes between the defendant’s conduct and the end result;
• or some event which occurs between the defendant’s conduct and the end result.

These circumstances are often described collectively as a novus actus interveniens.

Novus Actus Interveniens

Acts by Third Parties

If a third party intervenes in the events that result in the harm to the victim, the effect of these actions may be sufficient to break the chain of causation between the defendant and the victim’s harm. However, there are several limitations that arise in this respect.

The first of these is that, where both parties’ actions can be considered collectively to result in the harm suffered by the victim, both potential defendants are considered to have caused the harm. It does not matter that one defendant’s actions are the main cause of the harm and one defendant’s are not. All that is necessary, is that the defendant can be considered to a contributed significantly to the harm (R v Pagett (1983) 76 Cr App R 279). It is important to note that is most areas of the criminal law, and certainly in this circumstance, the word significant simply means more than minimally (R v Cheshire [1991] 3 All ER 670). Therefore, each defendant’s contribution must be assessed in relation to the particular harm charged.

Again, the punch example is helpful here. If defendant A throws a punch at the victim and this time connects with the punch and the victim is knocked to the ground. Following this, defendant B repeatedly kicks the victim in the head causing serious injuries from which the victim dies, B has caused the death. Whether A has also caused it depends on whether the punch remained an operating cause that contributed more than minimally to the death. The fact that it put the victim on the ground is not conclusive.

In practice, the acts of a third party will only break the chain of causation between the defendant and the victim’s harm if they are such as to render the defendant’s actions non-operable on the harm. In other words, if the defendant’s act can still be considered an operating and substantial (more than minimal) cause of the victim’s harm, the chain of causation will not be broken (R v Malcherek and Steel [1981] 2 All ER 422).

A free, deliberate and informed act by a third party may break the chain. A reasonable act of self-defence against the danger created by the defendant is different. In R v Pagett, the defendant used his former girlfriend as a human shield against the police whilst shooting at the police. The police returned fire and unfortunately killed the girlfriend. Pagett suggested that it was the actions of the police that had caused the death, not his own actions. It was held however, that the police had little choice but to defend themselves and therefore, their actions were not freely undertaken. The result was that it was Pagett who had caused the death because of his actions, the police shots did not break the chain of causation.

Foreseeability alone does not decide whether an intervention breaks the chain. The question is whether the defendant’s conduct remained a legally significant cause of the harm.

Medical Intervention

Where a victim is subject to an assault, it is foreseeable that they may need medical treatment, and it is also foreseeable that this medical treatment may be given wrongly or negligently. Poor medical treatment will only exceptionally break the chain of causation. Three judgments highlight this point.

In R v Jordan (1956) 40 Cr App R 152, the victim was admitted to hospital with stab wounds. When the victim died 8 days later, his wounds had largely healed and it was held that it was the palpably wrong medical treatment that caused the death, rather than the wounds themselves. The wounds were not an operating and substantial cause of the death.

In R v Smith [1959] 2 QB 35 on broadly similar facts to Jordan the defendant was unable to rely on the intervening medical acts, even though these were found to be extremely poor, because in this context, the victim’s wounds were still operating and substantial at the time of the death.

The difficulty in reconciling these two judgments and in particular reconciling Jordan with everything that has been discussed before in respect of causation is clear. In Smith it was stated that the chain of causation would only be broken if ‘it can be said that the original wounding is merely a setting in which another cause operates … only if the second cause is so overwhelming as to make the original wound merely part of history can it be said that the death does not flow from the wound’. Whilst it could be suggested that this approach might be valid where the faulty treatment relates to a completely different illness, it seems difficult to suggest that treatment, however overwhelmingly bad, if a direct result of the initial injury, should render the original injury less than substantial. Nevertheless, this is a distinction that must be drawn.

The test was expressed in R v Cheshire [1991] 1 WLR 844, where the Court of Appeal held that treatment must be independent of the defendant’s acts and so powerful a cause of death that the jury regard the defendant’s contribution as insignificant.

The effect of medical treatment on causation must be considered very carefully and the remaining effect of the initial wound must be looked at in detail. It is only safe to say that the chain of causation will only be broken where the original injury is insignificant in the face of the poor medical treatment. The fact that some trace of an injury remains is not decisive.

Acts of the Victim

The general position in respect of acts of victims is that an individual should be held responsible for acts that they undertake freely. In R v Kennedy (No 2) [2007] UKHL 38, the defendant supplied a syringe of heroin to an informed adult who freely injected himself. The supply did not cause death for the purposes of unlawful act manslaughter. In R v Field [2026] EWCA Crim 413, the Court of Appeal quashed a murder conviction where the jury directions allowed it to treat supplying whisky with a concealed intention to kill as sufficient, even if the victim freely chose to drink it. The prosecution’s appeal was heard by the Supreme Court on 13 October 2026. Judgment is awaited.

This approach does not apply where the acts of a victim cannot be considered to have been carried out freely. The most common situation where this principle is applied is where a victim is attempting to escape from a defendant. In R v Williams and Davis [1992] 1 WLR 380, the victim died after jumping from a car. The prosecution alleged an attempted robbery, but the evidence of what had happened in the car was slight. The manslaughter convictions were quashed. In this judgment it was held that two considerations should be made. In the first instance, the question should be asked as to whether it was reasonably foreseeable that some kind of harm was likely to result to the victim from the actions of the defendant. Secondly, whether the victim’s action, in the face of the defendant’s behaviour, was within a range of responses that might be expected of a victim in that situation.

Unfortunately, even this approach is slightly unclear. This is because in R v Roberts(1971) 56 Cr App R 95, it was held that where a victim’s actions were so daft that no reasonable person could foresee them, the chain of causation would be broken. Whereas, in Williams and Davis it was held that the particular characteristics of the victim should be taken into account, including whether they were of a particularly nervous disposition or whether they may have acted in panic. In R v Wallace [2018] EWCA Crim 690, the victim sought lawful euthanasia in Belgium after suffering severe injuries in an acid attack. The Court of Appeal held that neither his decision nor the doctors’ intervention necessarily broke the chain. Causation was a question for the jury.

The Eggshell Skull Rule

The position mentioned directly above in relation to the potentially nervous disposition of a victim, reflects the general rule that a defendant must take their victim as they find them. In R v Hayward (1908) 21 Cox CC 692, the defendant was found liable for his wife’s death after he threatened and chased her. The medical evidence attributed her collapse to fright and exertion acting on an unusual physical condition. The approach was taken further in R v Blaue [1975] 1 WLR 1411 where the defendant stabbed a woman who was a Jehovah’s Witness. As a result of her religious beliefs the victim refused a blood transfusion, which would have saved her life. The defendant was, however, found liable for her death on the basis that the religious beliefs of the victim could not be found to interfere with causation.

In unlawful act manslaughter, dangerousness is a separate question from causation. Would a sober and reasonable person, with the knowledge available to the defendant at the time, have recognised a risk of some physical harm? In R v Dawson (1985) 81 Cr App R 150 the robbers did not know about the victim’s heart condition. That hidden condition could not be used to establish that the robbery was dangerous. Once dangerousness is established, the defendant takes the victim as found.

Acts of God

An extraordinary natural event may break the chain of causation. In Southern Water Authority v Pegrum [1989] Crim LR 442, a pollution case, heavy rainfall did not excuse the escape of effluent. If a victim is punched and falls into a fast flowing river after heavy winter rain, the current is unlikely to displace the punch as a cause of drowning. If the victim is instead struck by lightning, the jury must consider whether the strike was an independent cause of death and the punch merely provided the occasion for it.

Summary of the Principles of Causation

• In most cases causation is a simple question of fact.
• The defendant’s actions do not need to be the sole or main cause of the victim’s harm. The defendant’s acts must simply contribute (more than minimally) to the harm.
• For a result crime, both factual and legal causation must be satisfied.
• Factual causation - ‘but for’ the defendant’s actions, would the harm have occurred when it did?
• Legal causation - was the defendant’s action an operating and substantial cause of the harm? If yes, the defendant caused the harm.
• Consider whether an intervening act displaced the defendant’s conduct as a legal cause of the harm. Foreseeability may be relevant but is not conclusive.
• Medical treatment will only break the chain if it is so independent and potent a cause that the defendant’s contribution to the death is insignificant.
• A defendant must take their victim as they find them (eggshell skull rule).

Cite This Module

To export a reference to this article please select a referencing style below:

• APA
• MLA
• MLA-7
• Harvard
• Vancouver
• Wikipedia
• OSCOLA