Criminal Law- Actus Reus


The words Actus Reus (AR) come from the Latin words meaning ‘Guilty Act’. This is an element that is needed in nearly all criminal offences, for there to have been a crime in their first place.

When discussing the AR, I will be referring to crimes in general, no one specific one. There are acceptations to many principles, therefore I will just be covering the basic ones repeating to acts and omissions. Case descriptions of the ones I have used can be located at the bottom of the post.



The general principles of the AR is that the conduct must be voluntary. This basically means that the act must have been committed under the free will of the Defendant, and they intended to do what they did. This is relatively easy to prove as the prosecution merely have to prove that the defendant was in control of their own body of the time the crime was committed. If they were not in control of their body and this can be proven, then they will be acquitted.



Most offences are committed by a positive act, however there are some cases where an omission may satisfy the AR of a crime.

An omission is where someone may cease to act, however the ‘non-act’ causes an offence to be committed. An example of this is where someone leaves an exposed live electric wire one a construction site, and goes on their break. The victim then comes along and gets shocked by the wire. In a case like this, the defendant had not made a positive act, however it has caused harm to the victim, and it would be unjust for them not to be convicted of a crime.

In the UK, for someone to be guilty of an omission there must be an existing duty of care owed from the defendant to the victim. If the victim was owed a duty, then it must be proven that the party who owed a duty actually breached that duty. By breaching this duty, they are falling below the reasonable standard of care that they are expected to retain.

A duty can arise out of 4 situations:

  1. A contract: failure to meet the terms of a contract may lead to the breach in a duty. For example, failure to meet a contract may endanger lives. They duty may not be owed only to the other party in the contract, but also any other person who may be effected. The Case authority for this is R v Pittwood.
  2. A relationship: The pre-existence of a close relationship may constitute there to be a duty of care owed from one party to another. For example, from parent to child or spouse to spouse. The case authority for this is R v Gibbins and Proctor.
  3. The assumption of care for another: where someone voluntarily takes on the care of another who is unable to care for themselves. This inability to take care may come from age, disability or any other condition. The case authority for this is R v Instan or R v Stone and Dobinson.
  4. Creating a dangerous situation: if the defendant created a dangerous situation, they therefore owe a duty of care to anyone which this danger may harm. They must take steps in order to mitigate this danger. The cause authority for this is R v Miller.



The second part to the AR is making sure that Causation is satisfied. There are two parts to causation, Factual Causation and Legal Causation.

Causation is the link between the act or omission and the result. Therefore, causation is only relevant with result crimes. Result crimes are those in which a specific result must have occurred in order for there to be a crime in their first place. For example, for someone to be convicted of Murder, someone must have died. If someone was to get convicted of Rape, someone must have been raped, and so on.


Factual Causation

This is based on a question of fact. What is known as the ‘But For’ test determines whether this is satisfied. This is where the prosecution ask “But for the defendants actions or omissions, would the victim have suffered the harm?”. If the answer is no then they will proceed to legal causation. If the answer is yes, then the defendant will be acquitted as it means the defendants actions did not cause the result. This is relatively easy in most cases for the prosecution to satisfy. The case authority for the ‘but for’ test is R v White.


Legal Causation

There are 5 legal principles in which supply a substantial link between the conduct and the result.

  1. Consequences must be attributable to a culpable act- R v Dalloway.
  2. The culpable act must be a more than minimal cause of the result- R v Pagett.
  3. The act does not have to be the only reason for the result to have occurred- R v Benge.
  4. You must take your victim as you find them (also known as the eggshell skull rule)- R v Blaue.
  5. The chain of causation must not be broken by any 3rd The case authority for this is R v Cheshire where is stated that the intervention of the third party must be so independent and so potent that it made the original act insignificant.


Case Details

R v Pittwood– The defendant was employed to close and left the train crossing barriers. He went on his lunch break and a train collided with a horse and cart and the driver died. The defendant was convicted as he owed a contractual duty of care.


R v Gibbins and Proctor– Husband and wife failed to feed 7 year old child and they died as a result of starvation. They had a duty of care established through relationship.


R v Stone and Dobinson– husband and wife took in a relative of the husband, who was sick. They failed o provide adequate care for her and she died as a result. They made attempt to seek medical help, but sufficient effort was not made. A duty had arisen out of the assumption of responsibility to care for her by taking her in.


R v Instan– the defendant lived with their Aunt who fell sick and contracted gangrene. They failed to seek any medical help or provide any care for her aunt. A duty had arisen though the assumption of responsibility of another.


R v Miller– a man left a cigarette on an armchair and fell asleep. He then awoke to find the chair was catching alight. He then went into the next room and fell asleep again. Therefore, he created a dangerous situation and did nothing to mitigate it.


R v White– poison was put into mother’s drink by a son in hope to inhered the estate. She died of a heart attack before drinking, and therefore the son was only liable for attempted murder.


R v Dalloway– A horse and cart rider was not holding the reins of the horse. A child ran out in front and was killed. Not holding onto the reins was a culpable act.


R v Paggett– A man used his pregnant wife as a human shield whilst having a firefight with the police. He made the first shot. The police shot and killed his pregnant wife. The court found that it was reasonably foreseeable that if the man shot, the police would return fire and could potentially hit the pregnant women, therefore he played a more than minimal role in her death.


R v Benge– A train driver read the train timetable wrong and set off driving a train when there was maintenance on the railway. However, at the same time, the lookout man was not standing far enough up the railway, and the train killed a worker. The train driver was convicted there can be more than one reason for the death.


R v Blaue– A Jehovah Witness was stabbed and because of this refused a blood transfusion that would have saved her life. The eggshell skull rule was applied meaning the defendant took the chance by stabbing her, this is might kill her. It does not matter on any other circumstance whether she could have survived.


R v Cheshire– Medical negligence stating that for a doctor to break the chain of causation, they must do something that is so independent and potent that is makes the original act of why then were under the care of the hospital insignificant


There is other case authority for these principles. These are the ones which my University teaches on the syllabus.



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