Lecture 2 – Criminal Law
Principles of criminal liability I: Actus Reus
What is a crime?
Although “criminal law” lacks a universal definition, it is generally accepted that a
criminal act will usually involve a “public wrong”
Crimes are generally acts that have harmful effect on the public, as opposed to
private interests (e.g. a party to a contract)
Crime is crime because it consists of wrongdoing which directly and in serious degree
threatens the security or well-being of society
What is criminal liability?
A person will be considered to have “criminal liability” if they are put on trial and
found guilty of committing a criminal offence
Conduct may be deemed criminal by statute (and Act or Parliament) or by common
law
If a persona is charged with a criminal offence the prosecution will normally be
brought by the Crow Prosecution Service (CPS) in the name of the crown
The court (either Magistrates’ or Crown Court) will then decide the guilt of the
defendant (the person being charged)
The prosecution bears the burden of proof for establishing the guilt of anyone who is
charged with a criminal offence (i.e. a defendant)- if this cannot be done then there
can be no conviction (i.e. guilty verdict) – Woolmington v DPP (1935)
The prosecution must prove the defendant’s guilt “beyond reasonable doubt”
What are the elements of a crime?
The Actus Reus the defendant did a “guilty act” the conduct element
The Mens Rea the defendant committed the “guilty act” with a “guilty mind”
intention
The defendant had no defence in law self-defence or defence of someone else
The Actus Reus of a criminal offence
It is a fundamental principle of English criminal law that a person may not be
convicted of a crime unless they have behaved in an unlawful way.
A defendant cannot be convicted of a criminal offence based on just their thoughts,
there must be a criminal act/ failure to act (MUST be an Actus Reus)
Every single criminal offence has an Actus Reus, if there is no Actus Reus then the
offence will not have been committed
In criminal trials the burden of proof will be on the prosecution to prove ‘beyond
reasonable doubt’ that the defendant performed the Actus Reus. If this cannot be
done, the defendant will not be criminally liable for the offence with which they have
been charged.
Three types of Reus element
Conduct (where D performs a positive act or omission)
Consequence (where D causes a result)
Circumstances (where certain surrounding circumstances lead to liability)
o Any one or more of these may be required for any given criminal offence
, Lecture 2 – Criminal Law
o E.g. theft (conduct + circumstances), murder (circumstances, conduct +
consequences)
Figure from Monaghan, criminal law directions
Requirement of Voluntariness
There is a general rule that the actus Reus elements of an offence must be voluntary
in order for criminal liability to be imposed. Where the Actus Reus is involuntarily
performed, there is no criminal liability.
“A person… who through no fault of his own becomes unconscious while driving, for
example, being struck by a stone, or by being taken ill, ought not to be liable at
criminal law” obiter dicta per Humphreys J in Kay v Butterworth 1945
“[I]n Kay v. Butterworth... the judge, after emphasizing that drowsiness or sleep
would be no excuse, said that ‘he did not mean to say that a person should be made
liable at criminal law who through no fault of his own became unconscious while
driving; for example, if he were struck by a stone or overcome by a sudden illness; or
the car was temporarily out of control by his being attacked by a swarm of bees’”
(per Lord Goddard CJ in Hill v Baxter [1958] 1 QB 277).”
“…there may be cases where the circumstances are such that the accused could not
really be said to be driving at all. Suppose he had a stroke or an epileptic fit, both
instances of what may properly be called acts of God; he might well be in the driver's
seat even with his hands on the wheel, but in such a state of unconsciousness that
he could not be said to be driving.”
“A blow from a stone or an attack by a swarm of bees I think introduces some
conception akin to novus actus interveniens”. (per Lord Goddard CJ in Hill v Baxter
[1958] 1 QB 277).
Principles of criminal liability I: Actus Reus
What is a crime?
Although “criminal law” lacks a universal definition, it is generally accepted that a
criminal act will usually involve a “public wrong”
Crimes are generally acts that have harmful effect on the public, as opposed to
private interests (e.g. a party to a contract)
Crime is crime because it consists of wrongdoing which directly and in serious degree
threatens the security or well-being of society
What is criminal liability?
A person will be considered to have “criminal liability” if they are put on trial and
found guilty of committing a criminal offence
Conduct may be deemed criminal by statute (and Act or Parliament) or by common
law
If a persona is charged with a criminal offence the prosecution will normally be
brought by the Crow Prosecution Service (CPS) in the name of the crown
The court (either Magistrates’ or Crown Court) will then decide the guilt of the
defendant (the person being charged)
The prosecution bears the burden of proof for establishing the guilt of anyone who is
charged with a criminal offence (i.e. a defendant)- if this cannot be done then there
can be no conviction (i.e. guilty verdict) – Woolmington v DPP (1935)
The prosecution must prove the defendant’s guilt “beyond reasonable doubt”
What are the elements of a crime?
The Actus Reus the defendant did a “guilty act” the conduct element
The Mens Rea the defendant committed the “guilty act” with a “guilty mind”
intention
The defendant had no defence in law self-defence or defence of someone else
The Actus Reus of a criminal offence
It is a fundamental principle of English criminal law that a person may not be
convicted of a crime unless they have behaved in an unlawful way.
A defendant cannot be convicted of a criminal offence based on just their thoughts,
there must be a criminal act/ failure to act (MUST be an Actus Reus)
Every single criminal offence has an Actus Reus, if there is no Actus Reus then the
offence will not have been committed
In criminal trials the burden of proof will be on the prosecution to prove ‘beyond
reasonable doubt’ that the defendant performed the Actus Reus. If this cannot be
done, the defendant will not be criminally liable for the offence with which they have
been charged.
Three types of Reus element
Conduct (where D performs a positive act or omission)
Consequence (where D causes a result)
Circumstances (where certain surrounding circumstances lead to liability)
o Any one or more of these may be required for any given criminal offence
, Lecture 2 – Criminal Law
o E.g. theft (conduct + circumstances), murder (circumstances, conduct +
consequences)
Figure from Monaghan, criminal law directions
Requirement of Voluntariness
There is a general rule that the actus Reus elements of an offence must be voluntary
in order for criminal liability to be imposed. Where the Actus Reus is involuntarily
performed, there is no criminal liability.
“A person… who through no fault of his own becomes unconscious while driving, for
example, being struck by a stone, or by being taken ill, ought not to be liable at
criminal law” obiter dicta per Humphreys J in Kay v Butterworth 1945
“[I]n Kay v. Butterworth... the judge, after emphasizing that drowsiness or sleep
would be no excuse, said that ‘he did not mean to say that a person should be made
liable at criminal law who through no fault of his own became unconscious while
driving; for example, if he were struck by a stone or overcome by a sudden illness; or
the car was temporarily out of control by his being attacked by a swarm of bees’”
(per Lord Goddard CJ in Hill v Baxter [1958] 1 QB 277).”
“…there may be cases where the circumstances are such that the accused could not
really be said to be driving at all. Suppose he had a stroke or an epileptic fit, both
instances of what may properly be called acts of God; he might well be in the driver's
seat even with his hands on the wheel, but in such a state of unconsciousness that
he could not be said to be driving.”
“A blow from a stone or an attack by a swarm of bees I think introduces some
conception akin to novus actus interveniens”. (per Lord Goddard CJ in Hill v Baxter
[1958] 1 QB 277).
